Ever since the pioneering work of Darwin and Wallace, evolutionary biologists have tried to understand the evolutionary dynamics of genetic systems. A range of theories on the rates of evolution-from static to gradual to punctuated to quantum-have been developed, mostly by comparing morphological changes over geological timescales as described in the fossil record. However, new paleontological, experimental, molecular, and genomic investigations have injected a tremendous amount of new data and fresh perspectives, offering valuable insights on the rates of evolutionary change, particularly in those fast-evolving genetic systems.Rapidly Evolving Genes and Genetic Systemscaptures these recent exciting developments by bringing together information from morphological, molecular, cellular, developmental, and genetic investigations of both natural and experimental populations across a diversity of life forms. It provides case studies that exemplify rapid evolution, and showcases the diversity of rapidly evolving genes and genetic systems, emphasizing the extremely important roles that they play in adaptation, speciation, and the generation and maintenance of a diversity of biological traits and properties.