History of LSD
The psychedelic drug/ entheogen LSD was first synthesized by the Swiss chemist Albert Hofmann in the Sandoz (now Novartis) laboratories in Basel, Switzerland in 1938.  It wasn't until 5 years later on April 16th, 1943, that the psychedelic properties were discovered.

# History
The Sandoz laboratory had undertaken a research program aimed at isolating the active constituents of medicinal plants so that they could be produced in the laboratory and later precisely dosed for accurate administration to patients. Dr. Hofmann eventually began researching the ergot fungus and alkaloids which could be derived from it. Ergot was traditionally used by midwives as an ecbolic, a medication used to induce childbirth, and early 20th century research indicated that the various compounds in ergot had other effects on the body as well, prompting further research.
After Dr. Hofmann succeeded in synthesizing ergobasine (which became the preeminent uterotonic), he began experiments with other molecules based around the central lysergic acid component shared by ergot alkalines. Lysergic acid diethylamide, the 25th lysergic acid derivative he synthesised (hence the name LSD-25) was developed initially as a probable analeptic, a circulatory and respiratory stimulant, based on its structural similarity to another known analeptic, nikethamide (nicotinic acid diethylamide). However, no extraordinary benefits of the compound were identified during animal tests (though laboratory notes briefly mention that the animals became "restless" under its effects), and its study was discontinued.

## Bicycle Day
The psychedelic effects of LSD were unknown for the next five years. Dr. Hofmann writes in LSD: My Problem Child that a "peculiar presentiment" prompted him to revisit LSD-25. While re-synthesizing the compound for further study, he became dizzy and was forced to stop work:
Last Friday, April 16, 1943, I was forced to interrupt my work in the laboratory in the middle of the afternoon and proceed home, being affected by a remarkable restlessness, combined with a slight dizziness. At home I lay down and sank into a not unpleasant intoxicated-like condition, characterized by an extremely stimulated imagination. In a dreamlike state, with eyes closed (I found the daylight to be unpleasantly glaring), I perceived an uninterrupted stream of fantastic pictures, extraordinary shapes with intense, kaleidoscopic play of colors. After some two hours this condition faded away.
Three days later, on April 19, 1943 (known as Bicycle Day), Dr. Hofmann intentionally ingested 250 g of LSD, which he hypothesized would be a threshold dose, based on other ergot alkaloids.  In reality, this is a fairly substantial dose and the threshold would actually be around 25 g. Hoffman wrote:
By now it was already clear to me that LSD had been the cause of the remarkable experience of the previous Friday, for the altered perceptions were of the same type as before, only much more intense. I had to struggle to speak intelligibly. I asked my laboratory assistant, who was informed of the self-experiment, to escort me home. We went by bicycle, no automobile being available because of wartime restrictions on their use. On the way home, my condition began to assume threatening forms. Everything in my field of vision wavered and was distorted as if seen in a curved mirror. I also had the sensation of being unable to move from the spot. Nevertheless, my assistant later told me we had traveled very rapidly.
Dr. Hofmann summoned a doctor, who could find no abnormal physical symptoms other than extremely dilated pupils. After spending several hours terrified that his body had been possessed by a demon, that his next door neighbour was a witch, and that his furniture was threatening him, that Albert Einstein was chasing him with a kitchen knife, Dr. Hofmann feared he had become completely insane.
 saw no reason to prescribe any medication. Instead he conveyed me to my bed and stood watch over me. Slowly I came back from a weird, unfamiliar world to reassuring everyday reality. The horror softened and gave way to a feeling of good fortune and gratitude, the more normal perceptions and thoughts returned, and I became more confident that the danger of insanity was conclusively past.
    Now, little by little I could begin to enjoy the unprecedented colors and plays of shapes that persisted behind my closed eyes. Kaleidoscopic, fantastic images surged in on me, alternating, variegated, opening and then closing themselves in circles and spirals, exploding in colored fountains, rearranging and hybridizing themselves in constant flux. It was particularly remarkable how every acoustic perception, such as the sound of a door handle or a passing automobile, became transformed into optical perceptions. Every sound generated a vividly changing image, with its own consistent form and color ...
    Exhausted, I then slept, to awake next morning refreshed, with a clear head, though still somewhat tired physically. A sensation of well-being and renewed life flowed through me. Breakfast tasted delicious and gave me extraordinary pleasure. When I later walked out into the garden, in which the sun shone now after a spring rain, everything glistened and sparkled in a fresh light. The world was as if newly created. All my senses vibrated in a condition of highest sensitivity, which then persisted for the entire day.
    This self-experiment showed that LSD-25 behaved as a psychoactive substance with extraordinary properties and potency. There was to my knowledge no other known substance that evoked such profound psychic effects in such extremely low doses, that caused such dramatic changes in human consciousness and our experience of the inner and outer world.
Interest in the drug was revived after Dr. Hofmann's experiment, and the University of Zurich began conducting systematic human trials on both normal participants and psychiatric patients diagnosed with schizophrenia. In both cases, the predominant reaction was euphoria. Sandoz began producing LSD under the trade name Delysid for research, suggesting that the drug might be useful "to elicit release of repressed material and provide mental relaxation, particularly in anxiety states and obsessional neuroses" and also for self-experimentation by psychiatrists, "to gain an insight into the world of ideas and sensations of mental patients".

# Psychiatric use
LSD was introduced into the United States in 1948. Sandoz Laboratories marketed LSD as a psychiatric cure-all and hailed it as a remedy for everything from schizophrenia to criminal behavior, sexual perversions, and alcoholism. In psychiatry, the use of LSD by students was an accepted practice; it was viewed as a teaching tool in an attempt to enable the psychiatrist to subjectively understand schizophrenia. It was also showed great promise as a facilitating agent in psychedelic psychotherapy. In one study in the late 1950s, Dr Humphry Osmond gave LSD to alcoholics in Alcoholics Anonymous who had failed to quit drinking. After one year, around 50% of the study group had not had a drink  a success rate that has never been duplicated by any other means.
In the United Kingdom the use of LSD was pioneered by Dr Ronald Sandison in 1952, at Powick Hospital, Worcestershire. A special LSD unit was set up in 1958. After Dr Sandison left the hospital in 1964, medical superintendent Dr Arthur Spencer took over and used the drug until he retired in 1972. In all, 683 patients were treated with LSD in 13,785 separate sessions at Powick, but Dr Spencer was the last member of the medical staff to use it.
From the late 1940s through the mid-1970s, extensive research and testing were conducted on LSD. During a 15-year period beginning in 1950, research on LSD and other hallucinogens generated over 1000 scientific papers, several dozen books, and 6 international conferences, and LSD was prescribed as treatment to over 40,000 patients. Film star Cary Grant was one of many men during the '50s and '60s who were given LSD in concert with psychotherapy, in an effort to overcome 'homosexual tendencies'.  Many psychiatrists began taking the drug recreationally and sharing it with friends. Dr. Leary's experiments (see History of LSD below) spread LSD usage to a much wider segment of the general populace.
Sandoz halted LSD production in August of 1965 after growing governmental protests at its proliferation among the general populace. The National Institute of Mental Health in the United States distributed LSD on a limited basis for scientific research. Scientific study of LSD largely ceased circa 1980 as research funding declined, and governments became wary of permitting such research, fearing that the results of the research might encourage illicit LSD use. By the end of the century there were few authorized researchers left, and their efforts were mostly directed towards establishing approved protocols for further work with LSD in easing the suffering of the dying (See thanatotherapy) and with drug addicts and alcoholics.

# Resistance and prohibition
By the mid-sixties the backlash against the use of LSD and its perceived corrosive effects on the values of the Western middle class resulted in governmental action to restrict the availability of the drug by making any use of it illegal. Despite a history of positive results of judicious use under controlled circumstances, LSD was declared a "Schedule 1", even though this entails that the drug has a "high potential for abuse" and is without any "currently accepted medical use in treatment".  LSD was removed from legal circulation. To support this action, the United States Drug Enforcement Agency claimed:
Although initial observations on the benefits of LSD were highly optimistic, empirical data developed subsequently proved less promising ... Its use in scientific research has been extensive and its use has been widespread.  Although the study of LSD and other hallucinogens increased the awareness of how chemicals could affect the mind, its use in psychotherapy largely has been debunked.  It produces no aphrodisiac effects, does not increase creativity, has no lasting positive effect in treating alcoholics or criminals, does not produce a 'model psychosis', and does not generate immediate personality change.
However, drug studies have confirmed that the powerful hallucinogenic effects of this drug can produce profound adverse reactions, such as acute panic reactions, psychotic crises, and "flashbacks", especially in users ill-equipped to deal with such trauma.
They fail to mention that these "adverse reactions" are almost exclusively the result of a "psychedelic" dose, ~400g or more (typical dose is around 50-150g). The  set and setting can act as a catalyst for the mentioned negative experiences, as indeed with the positive.
As always with psychedelics, the rule is:  There are no bad trips, only bad people.

# Aldous Huxley
Renowned British intellectual Aldous Huxley was one of the most important figures in the early history of LSD. He was a figure of high repute in the world of letters and had become internationally famous through his novels Crome Yellow, Antic Hay and his dystopian novel Brave New World. His experiments with psychedelic drugs (initially mescaline) and his descriptions of them in his writings did much to spread awareness of psychedelic drugs to the general public and arguably helped to glamorize their recreational use, although Huxley himself treated them very seriously.
Huxley was introduced to psychedelic drugs by a friend, psychiatrist Dr. Humphry Osmond. Osmond had become interested in hallucinogens and their relationship to mental illness in the 1940s and during the 1950s he made extensive studies of a number of drugs including mescaline and LSD. As noted above, Osmond had some remarkable success in treating alcoholics with LSD.
In May 1953 Osmond gave Huxley his first dose of mescaline, at the Huxley home. Huxley subsequently recorded his experiences in the landmark book The Doors of Perception; the title was drawn from a quotation by British artist and poet William Blake, and Huxley's book in turn was the source of the name of American rock band The Doors. Huxley tried LSD for the first time in 1955, obtained from "Captain" Al Hubbard.
Hubbard is a remarkable and controversial figure in his own right and is almost equally important to the history of LSD as Huxley or Leary. Hubbard had become a 'freelance' apostle for LSD in the early 1950s after supposedly receiving an angelic vision telling him that something important to the future of mankind would soon be coming. When he read about LSD the next year, he immediately sought and acquired LSD, which he tried for himself in 1951.
Although he had no medical training, during the Fifties Hubbard worked at Vancouver's Hollywood Hospital with Ross McLean, with psychiatrists Abram Hoffer and Dr. Humphry Osmond, with Myron Stolaroff at the International Federation for Advanced Study in Menlo Park, and with Willis Harman at Stanford Research Institute (SRI) running psychedelic sessions with LSD.
At various times over the next twenty years, Hubbard also reportedly worked for the Canadian Special Services, the U.S. Justice Department and the U.S. Bureau of Alcohol, Tobacco & Firearms. It is also rumoured that he was involved with the CIA's MK-ULTRA project. How his government positions interacted with his work with LSD is unknown.
Hubbard is reputed to have introduced more than 6,000 people to LSD, including scientists, politicians, intelligence officials, diplomats, and church figures. He became known as the original "Captain Trips", travelling about with a leather case containing pharmaceutically pure LSD, mescaline, and psilocybin.

# Dr. Timothy Leary
A significant number of researchers disagreed with the government's assessment of LSD. Dr. Timothy Leary, a psychology professor at Harvard University, was the most prominent pro-LSD researcher. Leary claimed that using LSD with the right dosage, set (what one brings to the experience), and setting, preferably with the guidance of professionals, could alter behaviour in dramatic and beneficial ways.
Dr. Leary began conducting experiments with psilocybin in 1960 on himself and a number of Harvard graduate students after trying hallucinogenic mushrooms used in Native American religious rituals while visiting Mexico. His group began conducting experiments on state prisoners, where they claimed a 90% success rate preventing repeat offences. A student introduced Leary to LSD, and he then incorporated that drug into his research as his mental catalyst of choice. His experiments produced no murders, suicides, psychotic breaks, or bad trips. On the contrary, almost all of Leary's participants reported profound mystical experiences which they felt had a tremendous positive effect on their lives.
By 1962, faculty discontent with Leary's experiments reached critical mass. Leary was informed that the CIA was monitoring his research (see Government experiments below). Many of the other faculty members had harboured reservations about Leary's research, and powerful parents began complaining to the university about Leary's distribution of hallucinogenic drugs to their children. Further, many undergraduate students who were not part of Leary's research program heard of the profound experiences other students had undergone, and began taking LSD (which was not illegal at the time) recreationally. Leary described LSD as a potent aphrodisiac in an interview with Playboy magazine. Leary and another professor, Richard Alpert, were dismissed from the university in 1963.
Leary and Alpert, unfazed by their dismissals, relocated first to Mexico, but were expelled from the country by the Mexican government. They then set up at a large private mansion owned by William Hitchcock in New York, known as Millbrook, where they continued their experiments. Their research lost its controlled scientific character as the experiments transformed into LSD parties. Leary later wrote, "We saw ourselves as anthropologists from the twenty-first century inhabiting a time module set somewhere in the Dark Ages of the 1960s. On this space colony we were attempting to create a new paganism and a new dedication to life as art."
A judge who expressed dislike for Dr. Leary's books sentenced him to 30 years in prison for possession of half a marijuana cigarette (which was later reversed by the Supreme Court in Leary v. United States). Publicity surrounding the case further cemented Leary's growing reputation as a counter cultural guru. Around this time, President Richard Nixon described Leary as "the most dangerous man in America." Repeated FBI raids instigated the end of the Millbrook experiment. Leary refocused his efforts towards countering the tremendous amount of anti-LSD propaganda then being issued by the United States government, coining the slogan, "Turn on, tune in, drop out."
Many experts blame Leary and his antics for the near-total suppression of psychedelic research over the last thirty five years .

# Government experiments
LSD was the original centerpiece of the United States Central Intelligence Agency's top secret MK-ULTRA project, an ambitious undertaking conducted from the 1950s through the 1970s designed to explore the possibilities of pharmaceutical mind control. Hundreds of participants, including CIA agents, government employees, military personnel, prostitutes, members of the general public, and mental patients were given LSD, many without their knowledge or consent. The experiments often involved severe psychological torture, and many victims committed suicide or wound up in psychiatric wards. The researchers eventually concluded that LSD's effects were too varied and uncontrollable to make it of any practical use as a truth drug, and the project moved on to other substances. It would be decades before the US government admitted the existence of the project and offered apologies to the families of those who had died during the experiments.
The role of 'middle-men' like Al Hubbard (see above) is still little understood and it is likely to be many decades (if ever) before information about their activities is declassified. The precise relationships between government projects like MK-ULTRA and academic research is not yet known, but it is highly probable that agencies such as the American CIA were closely monitoring non-government research in this area. Hubbard is known to have had direct connections to several medical programs during the 1950s, gave LSD to thousands of people, and is known to have worked (possibly simultaneously) for a number of Canadian and American government agencies.
Although the subject is highly contentious, there are those who argue that, whilst LSD eventually proved too unpredictable to be useful as a chemical weapon, it may have found another intelligence use. It is claimed that government agencies such as the CIA may have covertly promoted LSD among American youth, seeing it as a means of undermining and destabilising the emerging alternative / underground culture and the growing anti-war movement.
It is also interesting to compare the fates of high-profile LSD advocate Timothy Leary and that of the notorious but elusive LSD chemist Augustus Owsley Stanley III. Leary was hounded by the police, the FBI and possibly also the CIA and was given a draconian prison sentence for possession of a minuscule amount of marijuana. It is generally accepted that much of the best 'street' LSD that circulated in the western United States and beyond in the late 1960s was manufactured by Owsley, who was immortalized in Tom Wolfe's The Electric Kool-Aid Acid Test.
When he was apprehended by police in California in late 1967, Owsley was reportedly found in possession of enough LSD to make at least 250,000 trips; notwithstanding his reputation as the world's top illicit LSD chemist, he attempted to argue that this huge quantity was for personal use.  After being found guilty, Owsley was given a relatively light sentence of two years, and despite his international reputation and his criminal record, he was subsequently allowed to emigrate to Australia.
There have also been persistent claims of connections between the CIA and members of the so-called "Brotherhood of Eternal Love", most focusing on the mysterious figure of Ronald Stark, a reputed criminal who was alleged to have links to both the CIA and to paramilitary organizations including the PLO, as well as allegedly overseeing one of the world's largest LSD manufacturing and distribution rings, which operated in Italy, France and Belgium.
Though no evidence has yet come to light in the West, it is presumed likely that the Soviet government conducted its own experiments on the properties of LSD during the Cold War.

# Recreational use
LSD began to be used recreationally in certain (primarily medical) circles. Some psychiatric and medical professionals, acquainted with LSD in their work, began using it themselves and sharing it with friends and associates. Among the first to do so was British psychiatrist Humphry Osmond, who first gave the drug to author Aldous Huxley and who coined the term "psychedelic" to describe its effects.
LSD historian Jay Stevens, author of the book Storming Heaven: LSD and the American Dream, has said that, in the early days of its recreational use, LSD users (who were at that time mostly academics and medical professional people) fell into two broadly delineated groups. The first group, which was essentially conservative and was exemplified by Huxley, felt that LSD was too powerful and too dangerous to allow its immediate and widespread introduction, and that its use ought to be restricted to the 'elite' members of society  artists, writers, scientists  who could mediate its gradual distribution throughout society. The second and more radical group, typified by Alpert and Leary, felt that LSD had the power to revolutionize society and that it should be spread as widely as possible and be available to all.
During the 1960s, this second 'group' of casual LSD users evolved and expanded into a subculture that extolled the mystical and religious symbolism often engendered by the drug's powerful effects, and advocated its use as a method of raising consciousness. The personalities associated with the subculture, gurus such as Dr. Timothy Leary and psychedelic rock musicians such as the Grateful Dead, Jimi Hendrix, and Jefferson Airplane soon attracted a great deal of publicity, generating further interest in LSD.
The popularization of LSD outside of the medical world was hastened when individuals such as Ken Kesey participated in drug trials and liked what they saw. Tom Wolfe wrote a widely read account of these early days of LSD's entrance into the non-academic world in his book The Electric Kool Aid Acid Test, which documented the cross country, acid-fueled voyage of Ken Kesey and the Merry Pranksters on the psychedelic bus "Furthur" and the Pranksters' later experimentation with group use of LSD at the so-called Acid Tests.
LSD became a headline item in early 1967, largely thanks to The Beatles. Paul McCartney made highly publicized admissions about his and the group's LSD use in press and TV interviews; earlier in the year, British tabloid News of the World ran a sensational three-week series which claimed to blow the lid on 'drug parties' hosted by rock group The Moody Blues and attended by leading stars including Donovan, The Who's Pete Townshend and Cream drummer Ginger Baker. Largely as a result of collusion between News of the World journalists and the London Drug Squad, many pop stars including Donovan, and Mick Jagger and Keith Richards of The Rolling Stones were busted for drug possession, although none of the arrests involved LSD.  The first ever home grown UK 'acid lab' that got busted was in 1969  up to then all LSD had been imported from the U.S., or was remnant produce of Sandoz before it stopped producing LSD. The lab, in Kent, and a flat in London were raided simultaneously and quantities of equipment and LSD seized along with the two men who had been making the LSD; Quentin Theobald and Peter Simmons.
The music of groups including The Beatles had also begun to show the obvious influence of their experiences with LSD. John Lennon wrote a song which many assumed referred to LSD, "Lucy in the Sky with Diamonds", although John Lennon always dismissed the connection as coincidence; the source of the title (which has been confirmed by others in the group) was Lennon's son Julian, who described the subject of a drawing he had made of a school friend (one Lucy O'Donnell).  Lennon and Harrison, however, had been experimenting with the drug since early 1966  they were given their first trips by their dentist at a party. The songs "She Said She Said" (the line,'I know what it's like to be dead' is from an LSD trip the Beatles took with actor Peter Fonda. Fonda said those words repeatedly to John Lennon during the acid trip) and "Tomorrow Never Knows" (many lines of which Lennon borrowed from Leary's "The Psychedelic Experience") from the album Revolver were clearly about LSD trips.  During that same time, bands such as Pink Floyd, Jefferson Airplane, and the Grateful Dead helped give birth to a genre known as "psychedelic rock" or acid rock.
LSD was evidently in limited recreational use in Australia in the early 1960s, but is believed to have been  initially restricted to those with connections to the scientific and the medical communities. LSD overdose was suggested as a possible cause in the still-unsolved deaths of CSIRO scientists Dr Gilbert Bogle and his lover Dr Margaret Chandler, whose naked bodies were found beside the Lane Cove River in Sydney after a New Year's Eve party in on January 1, 1963.
Large quantities of LSD began to appear in Australia around 1967, and soon permated the music scene and youth culture in general, especially in the capital cities. The major source of supply during this period is believed to have been American servicemen visiting Australia (mainly Sydney) from Vietnam on 'rest and recreation' (R&R) leave, although the growing connections between American and Australian organized crime in the late 1960s may also have facilitated its importation. Recreational LSD use among young people was on a par with that in other countries in Australia by the early 1970s and continued until late in the decade. LSD is not believed to have been manufactured locally in a significant quantity (if at all) and most if not all supplies were sourced from overseas.
During the late 1960s and early 1970s, the drug culture adopted LSD as the psychedelic drug of choice, particularly amongst the hippie community. However, LSD dramatically decreased in popularity in the mid-1970s. This decline was due to negative publicity centred on side-effects of LSD use (most misleading or patently false), its criminalization, and the increasing effectiveness of drug law enforcement efforts, rather than new medical information. The last country to produce LSD legally (until 1975) was Czechoslovakia; during the 1960s, high-quality LSD was imported from the communist country to California, a fact appreciated by Leary in The Politics of Ecstasy.
The availability of LSD had been drastically reduced by the late 1970s due to a combination of governmental controls and law enforcement. The supply of constituent chemicals (notably ergotamine tartrate) were placed under tight surveillance and government funding for LSD research was almost totally eliminated. These efforts were augmented by a series of major busts in England and Europe. One of the most famous was "Operation Julie" in Britain in 1978; it broke up one of the largest LSD manufacturing and distribution operations in the world at that time, headed by chemist Richard Kemp. The group targeted by the Julie task force were reputed to have had links to the mysterious Brotherhood of Eternal Love and to Ronald Stark.
The fifteen defendants included two highly qualified chemists, two doctors of medicine, a teacher, and the American author David Solomon, a friend to Timothy Leary and a reputed "walking encyclopaedia" of drugs culture. The defendants were caught by a lengthy operation that involved police officers  one of them named Julie  who posed as hippies in the Welsh hills and on London council estates. They eventually located two large 'acid factories' in a farmhouse near Tregaron in West Wales and in a house in Hampton Wick. One of the police who raided the London factory reportedly ignored warnings from the occupants about a large amount of LSD that had been spilled in the room, and had to be hospitalized after absorbing the volatile chemical through skin contact.
Several of the conspirators were reputed to have made more than 1 million each and on their arrest  they joked with detectives that their business acumen merited a Queen's Award for Exports. Kemp had allegedly become convinced that LSD could "liberate" people's minds and assist harmonious social relationships and it was claimed at the time of his arrest that Kemp and his associates had stockpiled enough LSD to make millions of trips.
As a recreational drug, LSD has remained popular among certain segments of society. Traditionally, it has been popular with high school and college students and other young adults. LSD also has been integral to the lifestyle of many individuals who follow certain rock music bands, most notably the Grateful Dead. Older individuals, introduced to the hallucinogen in the 1960s, also still use LSD.
LSD made a comeback in the 1990s, especially through the acid house scene and raver subculture.  However, the current average dosage unit is approximately 30 to 75 micrograms, a significant decrease from the 1960 average dosage unit of 200 to 300 micrograms. Lower doses may account for the relatively few LSD-related psychiatric emergencies during this period. LSD use and availability declined sharply following a raid of a large scale LSD lab in 2000 (see LSD in the United States).
Although retail-level distribution of LSD is known to sometimes take place at public events that feature music that appeals to users, such as certain kinds of concerts and all-night raves, users at the fringes of the distribution chain typically obtain small quantities of LSD from friends and acquaintances in relatively private exchanges.