This greatly expanded and revised edition contains more than 1,000 entries, covering everything from common everyday foods to the latest in genetic research--and beyond. Each substance's properties are objectively described based on the latest scientific evidence. Included are substances that not only claim to improve thinking and other brain functions, but those that are thought to help prevent brain damage and degeneration, prevent aging and extend the human lifespan, enhance social skills and moral behavior, induce altered states of consciousness, and improve mood, stamina, and energy.