Last and First Men by William Olaf Stapledon (British, 1930)

Summary:
A nameless narrator introduces himself as one of the last men and forewarns that his story is to be seen as a cautionary tale for us, the current human kind. He urges humanity to mend its ways and prevent the sorrow it caused to its descendants in the first place.
 The first evolution of men engaged in an never ending series of wars. While world powers claim to strive towards peace, the disagreement on ways to achieve it lead to frictions that eventually blow out into full-fledged wars. As fossil fuels become scarce, the first men approach their end. The second evolution of men are nearly brought to extinction by the Martians, who do not regard humans as sentient beings. In a desperate effort to fight the Martians back, the second men use a biological weapon against the Martians; while the weapon succeeds in getting rid of the enemies, it also wipes out the human race.
 Once the third men's intellectual development reaches its peak, their major goal is to produce the finest technology. Third humanity's efforts lead them to the creation of the fourth type of humanity, characterised by their super intelligence in contrast with their underdeveloped bodies. In yet another ironic turn of events, the fourth men regard their creators and ancestors as inferior and annihilate them. However, the fourth evolution’s existence proved to be devoid of joy and passion, for which they resolve to engineer a fifth species of men, who are to be equally sentimental, intellectual and physical. When Earth becomes uninhabitable, the fifth humanity emigrates to Venus and, after annihilating the native population, the harsh conditions prevent them from adjusting to the new planet. Once the tectonic movements have brought more land to the predominantly aquatic planet. This species starts to actually thrive in their new home. As a result, the fifth species creates a new type of humanity; this time, the sixth kind of human kind manages to completely adapt to life on Venus throughout the generations, although they become far more rustic than their predecessors. Their end comes when they make the same errors as the first men. The seventh evolution stands out for their wings; it is not until million years later that a mutation gives way to a new wingless subspecies which re-develops technology. While the eighth men are not the smartest, they are intellectually developed enough to design their successors, who are bound for Neptune as Venus is facing destruction​. The rough conditions of the new planet push the Ninth men to become savages who care only for survival. After several years, the human race transforms into various shapes most suitable for life in the wild; the cycle repeats once more with the species destroying itself through war, followed by the rise of a new generation bent on achieving perfection. This obsession leads to the creation of the sixteenth men; with them begins a new era of constant progress. However, the sixteenth men's plan to create an improved version of themselves fails; the seventeenth men are flawed and unable to reach full intellectual capacity; therefore, they are quickly replaced by the eighteenth men. This last species evolves to the point that their physical features are so varied as to make it seem there are various species. Additionally​, they are so advanced that they practice a more liberal sexuality; the last men have ‘sub-sexes’ that allow them to relate in new and more fulfilling ways. This last species meets its end when the sun grows so hot that it destroys the whole solar system. In a desperate effort to perpetuate life, the eighteenth men create a virus and send it out to space in hopes that it will put in motion the creation of more sentient beings.

Another summary:
One of the Last Men on Earth warns us with his story about what is going to happen to humanity. He describes several evolutions of men. The First Men went through a lot of wars due to disagreements on how to achieve peace. Then, problems about fossil fuels, social systems and mental health came up, so almost all the First Men started to die. The Second Men survived the explosion in Patagonia. They were physically very different from the other men as they modified themselves genetically. They were invaded by Martians, and the weapon they used to end them, also affected them in a terrible way. The Third Men were mostly interested in artistic intelligence. They wanted to create men that could solve any kind of human problem; the result of this technology was Fourth Men, who were very joyful and passionate. They tried to fix this and created the Fifth Men, who were a perfect balance between its mental, emotional, and physical parts. As the Earth was no longer habitable, these men colonized Venus. They created the Sixth Men who wanted to fly, so they created the Seventh Men. The Seventh Men designed the Eighth Men, who ended Venus and moved to Neptune. The Ninth Men were created there and adapted this planet for their needs. These men became wild, so the Tenth Men were mostly primitive and became extinct by a microorganism. However, other men were born from what was left of them until the Eighteenth Men or so-called Last Men came. They no longer looked like Men. They had a lot of capacities and had sub-sexes that made them have a much more fulfilling way to relate between them. The Sun became much bigger and destroyed everything. The Last Men sent a virus to space with the hope of a new type of men emerging from it.

Another summary:
The narrator describes how the First Men situation was marked by war; the European War, called the War to End War and unleashed by conflicts between France, Germany and England; the rivalry between Italy and France; the Anglo-French War; the conflicts between America and China; the growth of Germany and Russia and their subsequent war; the disintegration of the British Empire after the war and the League of Nations’ economic conflict caused by the demand for fuel. Also, they lived the foundation of the First World State, based on a system similar to the socialist guild, but fundamentally individualist, which subsequently collapsed because of the sudden failure of the supplies of coal and a psychological crisis that attacked the entire race. The First Men collapsed some million years after the destruction of the State, the men lived The First Dark Age, at which time the man lived an eclipse for a hundred thousand years in terrible conditions and then lived a Second Dark Age. After this, the race lived the rise of Patagonia and it's cult of youth, which came to an end after a fatal explosion in one of its mines that wreaked havoc on Earth, now largely uninhabitable and with very few survivors, from whom they derive the Second Men, which appeared around ten million years after the Patagonian disaster.
 These Men were characterized by being slightly different physically, for example, their upper stature and the shape of their skull or that of their neck, to mention some features. In the social aspect they also evolved, with a structure based on the unity, that went through varied periods of ups and downs. The improvement of the human being was a priority for them, for which they used genetic modification to create a human being that reached its maximum potential. After the invasion of the Earth from Mars, they started a war against the Martians in which they managed to end them and the Third Dark Age arrived.
 The Third Men, meanwhile, were characterized by being short-lived, having a special interest in the world of sense-experience and the arts rather than in science, their thinking was not systematic and also, at a certain point, began to have an obsessive interest in race and in the practice of vital art. They thought of creating a man who was capable of solving all human problems; The Fourth Men emerged from this project, and were especially concerned with biological evolution and social organization affairs, until at a certain point they began to feel oppressed and decided to confront their creators. As a solution to this situation, the Fourth Men, also known as the Great Brains, decided to manufacture artificial humans to replace them, so they created the Fifth Men, a species designedto compliy with the aspects that the Fourth Men considered necessary to improve and which was later responsible for the destruction of its own creators. They also focused on developing technology until it reached its greatest potential, to the point that they are able to adapt Venus to their needs and colonize it despite the resistance of the natives and create a new artificial species: the Sixth Men. This species had a special interest in the idea of ​​flying, so they designed the Seventh Men and gave them this feature.
 
 When they created the Eighth Men, they were well trained in handling, calculation and invention and specialized in engineering. They turned Venus into an uninhabitable place and moved to Neptune, where the Ninth Men lived; they adapted to that environment and gradually became wild, so their descendants, the Tenth Men were a totally primitive species and ended up being exterminated by a microorganism. Other species emerged from its remains; the Eleventh, Twelfth and Thirteenth Men, whose fates were similar to the Tenth. The Fourteenth Men were obsessed with perfecting the human being and his civilization; the Fifteenth Men were quite devout and sought to end the great evils and the ill-will, they also created the Sixteenth Men, a species that was characterized by its varied cultures that flourished one after another and for supporting highs and lows during its existence, in addition of creating the Seventeenth Men, an almost perfect species capable of communicating 'telepathically' that not long after was replaced by the Eighteenth Men. This species is the last of Men, they see themselves as more human and more animals than their previous versions, they are totally different from the first species in terms of customs and social and cultural values, in addition to their physical traits and abilities, they are fully aware of the wide variety of possible events in the cosmos and the inevitability of the end of the Men and consider its existence the supreme era of philosophy. Like its predecessors, the life of the Last Men comes to an end, this happens after Neptune becomes a place too hot to be inhabited and leaving the planet is no longer a viable option for Men, the heat burns everything in its path and the only places of refuge, the two poles, lose communication with each other and the only thing they have left before the end is to have group meetings to share comfort and give each other strength while they wait for the end and hope that in Some part of the galaxy new life may be born.

World view: Describes in a variety of aspects and with some consistency an imaginary state or society which is regarded as better, in some respects at least, than the one in which its author lives.
Future projections: It’s a fearful prediction of the possible outcomes of today’s actions. Thus, it warns us against the terrible disasters (e.g. overpopulation, war, climate change) which would follow if there is no change in direction.
Ideology: Explains how a better society came to be, in which sociopolitical institutions and individual relationships are organized to a more perfect principle than in the author's community.
Characters, plot and writing style: Black humor and satire are employed to expose, criticize or shame individuals or the society itself into improvement.
Classification: Dystopia