Nonlinear dynamo theory is central to our understanding of the magnetic structures of planets, stars and galaxies. This volume presents an updated and coherent view of recent advances in this significant and expanding area with contributions from some of the leading authors in the field. Both kinetic and dynamic approaches to the subject are considered with topics including fast dynamos, topological methods in dynamo theory, physics of the solar cycle and the fundamentals of mean field dynamo. This volume provides a useful source of reference for postgraduates and researchers in astrophysics and geophysics.