Laughter studies so far have lacked an interdisciplinary approach, hindering the integration of results. Work in philosophy focuses on why we laugh but lacks a basis in empirical data. Studies in neuroscience and linguistics rest on empirical data, but do not fully describe the phenomenon of laughter. This study describes both the nature of the laughable and laughter's integration into conversations. It addresses the problem by analyzing eight conversations. The results suggest laughter is integrated into the broader structure of conversation. It follows regular turn-taking structure in two types of adjacency pairs: 1) laughable-laugh, and 2)laugh-laugh. Laughter is also integrated into conversation as backchannel and as a speaker discourse marker. The nature of the laughable is incongruity. Incongruous utterances result from various techniques that present propositional content in an unreal way or consist of propositional content itself that is unreal. Understanding incongruity as an expression of the unreal interrelates various studies and theories of laughter. This book may appeal to philosophers, linguists, and humorists.