Extrusion Reactions presents a critical review of the reactions which presents a rupture of both of the bonds connecting an atom or a small group of atoms into a ring system. It discusses the loss of small fragments from cyclic structures under non-catalyzed conditions. It addresses those reactions wherein the major output and starting materials are cyclic. It demonstrates the general characteristics of the main classes of residua. Some of the topics covered in the book are the conditions for extrusion; types of concurrent reactions; choice of experimental conditions in extrusion; structural requirements for extrusion, and special cases of the reaction; extrusion from analogous systems; extrusions of carbon monoxide and carbon dioxide; and extrusion of sulfur dioxide and oxidized sulfur fragments. The extrusions of the elementary chalcogens: sulfur, selenium, and oxygen are fully covered. Extrusion of nitrogen from pyrazolines and 3H-pyrazoles are extensively discussed. An in-depth evaluation of the course of extrusion from pyrazolines is provided. The extrusion of nitrogen from triazolines and formation of aziridines from triazolines are also presented. A chapter is devoted to possible intervention of oxadiazolines and thiadiazolines in syntheses of oxirans. The book can provide useful information to chemists, students, and researchers.