Not many users of the world's two most popular drugs know the details of their chemical or biological effects; here's a good introduction.
Braun, a science writer and television producer, begins with alcohol, which was known to ancient Sumerians 5,500 years ago. Ethanol (the drinkable form of alcohol) is a waste product of the metabolism of sugar by yeast; it is poison to the yeast that produces it and (in sufficient quantities) to the human beings who drink it. So the body has developed complex ways of defending itself. Braun describes the progress of a shot of whiskey through the body, from the taste buds to the digestive tract, with amusing commentary on the journey. The alcohol's ultimate destination is the brain; scientists believe that it releases endorphins there, as do ether, valium, and morphine. Further chapters discuss alcohol's effects on sexual desire and performance, positive health benefits of moderate drinking, hangover cures, and current theories on the causes of alcoholism. Then caffeine gets a similar treatment, from its introduction into the Western world to its current popularity in forms ranging from espresso to soft drinks. Braun explains the decaffeination process (most of the caffeine removed from coffee is sold to soft-drink manufacturers) and explores such questions as whether caffeine aids mental processes (and which ones), to what extent caffeine is addictive, and how caffeine and alcohol interact (as in Irish coffee). Here, as in the chapters on alcohol, bits of interesting lore--women's protests against 18th-century coffeehouses, Theodore Roosevelt's impromptu endorsement of Maxwell House, the formation of the first Caffeine Anonymous group--add the human dimension to the scientific discussion. In the end, the author admits that caffeine was an indispensable aid to his writing of this book, but he has since moderated his use of both caffeine and alcohol.
An entertaining and informative discussion of both the scientific and cultural impact of caffeine and alcohol.