In May 1966, Zal Yanovsky and Steve Boone of the Lovin' Spoonful – an American folk-rock band then at the height of its success – were arrested in San Francisco, California, for possessing marijuana. Yanovsky, a Canadian by birth, expected that a conviction would lead to his deportation and a breakup of the band. To avoid this eventuality, the pair cooperated with law enforcement, revealing their drug source at a local party a week after the initial bust.
 The Lovin' Spoonful was the first popular music act of the 1960s to be busted for possessing illegal drugs. After Boone and Yanovsky's drug source was arrested in September 1966 and proceedings for his case began that December, the pair's cooperation with authorities was widely reported in the West Coast's burgeoning underground rock press, souring the band's reputation within the counterculture and generating tensions within the group. Yanovsky was fired by his bandmates in May 1967. The Lovin' Spoonful saw diminished commercial success that year, something some authors attribute to the fallout of the drug bust, but other commentators dispute this.
 In 1966, the Lovin' Spoonful was one of the most successful popular music groups in the U.S. Between October 1965 and June 1966, the band's first four singles reached the Top Ten of Billboard magazine's Hot 100 chart, two of which reached number two, and in March 1966 they recorded what became their biggest hit, "Summer in the City", which topped the U.S. charts in August. Originally formed in late 1964 in New York City's Greenwich Village neighborhood, the Lovin' Spoonful was among the earliest popularizers of the genre of folk rock. Other early folk-rock acts, like the Byrds and the Mamas & the Papas, relocated to the U.S.'s West Coast, but in 1966, as the center of the American pop music scene shifted towards San Francisco and Los Angeles, the Lovin' Spoonful remained based in New York City.
 The Lovin' Spoonful toured the West Coast several times in the second half of 1965. The band made their earliest West Coast appearances at San Francisco's Mother's Nightclub in late July and early August 1965, only weeks after the release of their debut single, "Do You Believe in Magic", which quickly propelled them to nationwide fame. The band played for two weeks at Mother's and also appeared at the hungry i nightclub. On October 24, the group headlined a dance party at the Longshoreman's Union Hall in the city's Fisherman's Wharf neighborhood. Organized by the concert production collective Family Dog Productions, the show marked one of the earliest events in San Francisco's psychedelic music scene.
 On May 20, 1966, the Lovin' Spoonful arrived in San Francisco for another tour of the West Coast. That day, Boone and Yanovsky attended a party in the city's Pacific Heights neighborhood at the home of Bill Love, the manager of The Committee, a San Francisco-based improv comedy group. Love, who knew Boone and Yanovsky through a mutual acquaintance, sold the pair marijuana, what was then an illegal drug. After Boone and Yanovsky left the party in their rental car, police pulled the pair over, searched the vehicle and discovered the drug.
 Boone and Yanovsky were arrested and spent the night in jail before being bailed out the following morning by the band's road manager, Rich Chiaro. Bob Cavallo, the band's manager, and Charles Koppelman, who had signed them to his entertainment company, flew to San Francisco to begin managing the situation, hiring the attorney Melvin Belli in the process. The band's two other members, John Sebastian and Joe Butler, were not informed on the details of the bust, and the band performed as scheduled on May 21 at the University of California, Berkeley's Greek Theatre, playing for an hour in-front of 5,500 concertgoers.
 At a meeting with San Francisco police and the District Attorney, Yanovsky was threatened with deportation back to his native Canada. Belli expressed to Yanovsky and Boone that they were unlikely to win on the merits of their case and that their only way to avoid charges was to cooperate with authorities. The two initially balked at the idea, but they relented to avoid Yanovsky being deported, something they expected would lead to a breakup of the band. Yanovsky and Boone cooperated with authorities to name their drug source, directing an undercover operative to their source at a local party on May 25. In exchange, all charges were dropped, their arrest records were expunged, the two did not need to appear in court and there was no publicity related to their arrest.
 Boone and Yanovsky's arrests marked the first time members of a popular music act in the 1960s were busted for illegal drugs. Three weeks later, on June 10, 1966, Donovan became the first high-profile British pop star to be arrested for possession of cannabis. Busts on the Rolling Stones, Buffalo Springfield, the Beatles and on Jimi Hendrix followed over the next three years. Boone suggests in retrospect that the Lovin' Spoonful's management had no plan in place on how to handle a drug bust, and he predicted that had it happened later in the decade, preparations would have likely been made ahead of time.
 Police initially arrested Bill Love's girlfriend, but she was released without being charged. Love's arrest followed in September 1966, and preliminary hearings for his case began in early December. Around that time, knowledge of Yanovsky and Boone's involvement as informants became more widespread on the West Coast, particularly in San Francisco. In an attempt to quash the story, the band's management offered to pay for Love's defense attorney or to pay for his silence regarding the matter, options which he refused. Love was convicted on June 5, 1967, on two counts of the sale of marijuana, and he was sentenced the following January.
 There were fliers that said, "Groupies: Don't fuck the Lovin' Spoonful – they're finks." ... His (Zal Yanovsky's) thoughts about the band, [the music, the business], and the generation of love, was shattered.
 – John Sebastian
 The underground press was critical of the band over Yanovsky and Boone's decision to act as informants. In early 1967, excerpts of the court transcript were photocopied and hung in public places across San Francisco. Chester Anderson, a local journalist active in the counterculture, distributed leaflets regarding the situation to underground newspapers, including the Berkeley Barb, the Los Angeles Free Press and the East Village Other. The Berkeley Barb was the first to cover the bust, placing a story on its front page in February 1967. Love led efforts to boycott the band. In July, he took out a one-page ad in the Los Angeles Free Press which related the story, called for readers to destroy their Lovin' Spoonful records and avoid their concerts and urged female fans to not have sex with the band.
 By early 1967, the Lovin' Spoonful's shows on the West Coast were sometimes picketed by members of the counterculture. Protesters carried signs which accused the band of being "finks" and traitors to the movement, and they encouraged fans to boycott the band and burn their records. Some authors suggest the bust and its fallout was the reason for the Lovin' Spoonful's absence from the Monterey International Pop Festival, a music festival held in June 1967 on California's Central Coast. The music festival signalled a major geographical shift in America's pop music scene, and the author Jon Savage suggests the Lovin' Spoonful's treatment by the counterculture stemmed from the broader inter-city rivalries between the West and East Coast amid the pop scene's transition.
 Among the Lovin' Spoonful's defenders was Ralph J. Gleason, the co-founder of the San Francisco-based rock magazine Rolling Stone. Gleason wrote a piece regarding the bust in the magazine's second issue, dated November 1967, in which he argued that the reaction against the band was worse than Yanovsky and Boone's decision to cooperate. He concluded that the band's treatment was, "the biggest underground cancer in the rock scene", and he encouraged readers to continue buying the band's records.
 The public revelations regarding Boone and Yanovsky's cooperation generated tensions within the band. In the months after the bust, Yanovsky began drinking more heavily, and his behavior both on- and off-stage became increasingly erratic. He often disagreed with the band's creative direction, which was being increasingly dictated by Sebastian, and Boone recalled that the relationship between the Sebastian and Yanovsky became stilted due to the latter's tendency towards rebelling rather than communicating his concerns directly. In late 1966, Boone and Yanovsky collaborated on a song, "The Dance of Pain and Pleasure", which they hoped could serve as catharsis for their situation, but the song was poorly received by their bandmates and the band's producer, Erik Jacobsen, and it was never recorded or developed further. In May 1967, Sebastian convened a band meeting in which he issued an ultimatum that he would leave the group unless Yanovsky was fired. In a subsequent group meeting at Sebastian's apartment, the band informed Yanovsky that he had been fired, and he last performed with the group on June 24, 1967.
 The Lovin' Spoonful saw diminished commercial success in 1967; after Yanovsky's departure, only one of the band's singles entered the American top 40. Boone and the author Hank Bordowitz later said that the counterculture's boycott hurt the band's commercial performance, Bordowitz suggesting that the band's loss of "counterculture credibility" effectively ended their commercial viability. The author Richie Unterberger counters that the effects of the boycott have likely been overestimated, since "most of the people who bought Spoonful records were average teenage Americans, not hippies". He instead connects the band's commercial struggles to the expanding popularity of the genre psychedelia, to which folk-rock acts struggled to transition, while he also contends that the Lovin' Spoonful's creative struggles likely stemmed from the bust and the resulting "spiralling personal difficulties".