The thesis of this book is that neither laughter nor humor can be understood apart from the feeling that underlies them. This feeling is a mental state in which people exclude some situation from their knowledge of how the world really is, thereby inhibiting seriousness where seriousness would be counterproductive. Laughter is viewed as an expression of this feeling, and humor as a set of devices designed to trigger it because it is so pleasant and distracting. Beginning with phonetic analyses of laughter, the book examines ways in which the feeling behind the laughter is elicited by both humorous and nonhumorous situations. It discusses properties of this feeling that justify its inclusion in the repertoire of human emotions. Against this background it illustrates the creation of humor in several folklore genres and across several cultures. Finally, it reconciles this understanding with various already familiar ways of explaining humor and laughter.