The book "Spatio-Temporal Dynamics and Quantum Fluctuations in Semiconductor Lasers" offers a comprehensive analysis of the complex spatio-temporal dynamics occurring in modern semiconductor lasers. It addresses fundamental theories and simulations that deal with the interactions between light and matter. The authors, Edeltraud Gehrig and Ortwin Hess, explain how microscopic carrier dynamics, spatially dependent light field propagation, as well as spontaneous emission and noise influence the properties of semiconductor lasers. Through microscopic simulations, the internal dynamics of various types of lasers, including in-plane lasers and vertical-cavity surface-emitting lasers, are examined in detail. The developed theories not only provide a foundation for interpreting measured emission characteristics but also offer valuable insights for the design of advanced semiconductor lasers.