In Laughter: A Scientific Investigation, published in 2000, neurobiologist Robert R. Provine examines humor as a function of social relationships. Using research from various social field experiments and exploring past ideas from such noted psychoanalysts as Sigmund Freud, Provine presents laughter in all its forms and even distinguishes between laughter and smiles. It also includes a section on neural disorders that are associated with laughter and the types of laughter therapy used by some psychologists today.

Twain was one of the most noted American humorists during the late nineteenth and early twentieth centuries, when many of his writings were published in magazines like the Atlantic Monthly. In 1925, ten years after Twain's death, Harold Ross founded The New Yorker, a magazine that would help to define humor in the modern era. In Fierce Pajamas: An Anthology of Humor Writing from "The New...