Those who are unfamiliar with the research literature on laughter and humor will find here a number of interesting observations and tidbits of information: laughter is primarily a social rather than a solitary phenomenon; in natural conversation, speakers laugh more than their audience; women laugh more at things that men say than vice versa; laughter tends to occur at the end of sentences and phrases rather than in the middle; we frequently laugh at comments that are not obviously funny; laughter is contagious; and you can't tickle yourself. Based on these and other findings relating to human (as well as chimpanzee) laughter, Provine proposes a number of hypotheses and speculates about the implications for our understanding of neuroscience, evolution, and human sociobiology.