Synchronization processes bring about dynamical order and lead to spontaneous development of structural organization in complex systems of various origins, from chemical oscillators and biological cells to human societies and the brain. This book provides a review and a detailed theoretical analysis of synchronization phenomena in complex systems with different architectures, composed of elements with periodic or chaotic individual dynamics. Special attention is paid to statistical concepts, such as nonequilibrium phase transitions, order parameters and dynamical glasses.Contents:Synchronization and Clustering of Periodic Oscillators:Ensembles of Identical Phase OscillatorsHeterogeneous Ensembles and the Effects of NoiseOscillator NetworksArrays of Limit-Cycle OscillatorsSynchronization and Clustering in Chaotic Systems:Chaos and SynchronizationSynchronization in Populations of Chaotic ElementsClusteringDynamical GlassesSelected Applications:Chemical SystemsBiological CellsNeural NetworksReadership: Graduate students and academics interested in complex systems.