Pihkal - A Chemical Love Story by Ann and Alexander Shulgin is about love and chemicals, in the most literal sense. Officially, it's a work of fiction. Thus, when agents of the Drug Enforcement Agency (DEA) came to raid the Shulgin's home some years after the first publication in 1991, the couple could always claim that specific persons or events were made up. The reason why the book did stir up attention from the DEA, though, is that it's not only a (fictionalized) autobiography but also a science book.
Even if you've never heard of Alexander Shulgin, it's most likely that you've heard of his research. He is a pharmacologist and chemist and throughout his long career, he developed and discovered hundreds of mind altering substances - designer drugs. Most famously, he rediscovered a type of phenetylamine called MDMA which is commonly known as ecstasy.
Shulgin did not only invent those drugs, but in the spirit of Aldous Huxley and Albert Hofmann, he tested them all on himself and took meticulous notes of his experiences. If he liked a certain substance, he would invite a selected group of friends to test it as well. The title of the book is thus ambiguous. The first part is about the lives and love of Ann and Alexander, but there is another love story: Pihkal is an acronym of 'Phenetylamines I have known and loved'. The authors don't advocate the mindless, recreational use of drugs, but they clearly like them and emphasize their therapeutic and spiritual potential.
Shulgin had a license to do research on such drugs, he even worked for the DEA. The reason why the government raided his lab and home, nonetheless, is in the second part of the book. Shulgin was afraid that his knowledge might eventually get lost and therefore included detailed descriptions how to synthesise all the drugs mentioned in the first part, including comments on dosage and effects. You would need to study chemistry to understand the instructions, but the comments and trip reports are highly interesting even for laymen.
Some parts of the book are a bit heavy on the new-age side and might be a bit naive, but overall, it strikes a good balance between the all too common glorification or demonisation of drugs. In 1997, the couple published a follow up called Tihkal - Tryptamines I have known and loved. It's the continuation of their story (including a description of the DEA raids) as well as some political essays and many new recipes. For anyone interested in the human mind (especially chemistry and neuropsychology), both books are highly recommended.