L vy processes are rich mathematical objects and constitute perhaps the most basic class of stochastic processes with a continuous time parameter. This book provides the reader with comprehensive basic knowledge of L vy processes, and at the same time introduces stochastic processes in general. No specialist knowledge is assumed and proofs and exercises are given in detail. The author systematically studies stable and semi-stable processes and emphasizes the correspondence between L vy processes and infinitely divisible distributions. All serious students of random phenomena will benefit from this volume.