Coffee just wouldn't be the same without that magical ingredient, Caffeine!
Howstuffworks "How Caffeine Works": by Marshall Brain
Frequently Asked Questions About Caffeine The name speaks for itself
Neuroscience for Kids -- Caffeine Don't try this at home
Caffeine Calculator "Got Caffeine?" from the National Sleep Foundation
Caffeine Content of Foods and Drugs from the Center for Science
in the Public Interest