Caffeine is the only FDA approved nonprescription or over the counter (OTC) stimulant medication for occasional use. The purpose of this pocket guide is to provide a summary of research information patterning to caffeine. Some of the information circulated over the years about the effects of caffeine lacks factual scientific basis. The text is divided into major headings of physiological and behavioral effects associated with caffeine consumption. The extensive information about caffeine is categorized and organized in tabular and concise form to facilitate reading and comprehension. It is a very quick and easy-to-use reference work.