Jack S. Margolis' Complete book of recreational drugs

A non-judgemental, non-advocatory guide to every recreational drug one is likely to encounter. Laid out in encyclopedia format, its entries include physical and psychological effects, lethal dosages, dependency information, and other known issues regarding each substance. Although a bit dated (Quaaludes are obsolete, for example, and the newer "designer drugs" aren't listed), it's still an amazing resource. If more people had been given this book instead of "Just say no," there would probably be a lot fewer drug-related deaths.