This chapter provides some ways to classify jokes into categories, discusses some theories about what makes something funny, and get into the caveats about why this work can be so difficult. This information can lay the groundwork for humor’s role in communication, personality, health, thought, and the like. Comedy alters mood, thought, stress, and pain. Jokes and laughter may play an important role in health, mental illness, marital bliss, education, and psychotherapy. Although a comprehensive model that explains every funny thing in the world would be quite complicated, humor definitely lends itself to study. Cynicism aside, experiments on comedy and mirth have generated amazing insights in the arts and sciences, leading to new ways to recognize, generate, and use funny material. As ubiquitous and intuitive as comedy seems to be, the grand theory and explanation of all humor remain elusive.