The field of dual catalysis has developed rapidly over the last decade, and these volumes define its impact on organic synthesis. The most important, basic concepts of synergistic, dual catalytic cycles are introduced, providing newcomers to the field with reliable information on this new approach to facilitating the synthesis of organic molecules. Background information and reliable procedures for challenging transformations in synthesis are presented, applying the concept of cooperative dual catalysis as a means of increasing molecular complexity in the most efficient manner. The most useful, practical, and reliable methods for dual catalysis combining metal catalysts, organocatalysts, photocatalysts, and biocatalysts are presented.