This volume covers a wide range of problems in the quantum mechanics of non-integrable systems, presented by experts in the field. The main part of the work concerns quantum chaos and dynamical aspects of chaos in particular. Among the subjects which are treated are: periodic perturbations, small denominators in quantum mechanics, tunnelling in the presence of a periodic perturbation, chaotic scattering, quantum maps, level statistics of chaotic systems and random matrices. The papers are concerned with mathematically rigorous derivations of results, as well as with their physical applications, such as scattering, ionization and tunnelling. The papers discuss recent results which have not been published in book form before. All contributors present new methods to approach quantum chaos rather than extending conventional techniques. This book is intended for specialists in the field of dynamical systems, quantum mechanics and stochastic processes. It can also serve as an introduction to graduate and postgraduate students of theoretical physics and mathematics.