Thermal processing in the subsecond range comprises modern, non-equilibrium annealing techniques which allow various material modifications at the surface without affecting the bulk. Flash lamp annealing (FLA) is one of the most diverse methods for short-time annealing with applications ranging from the classical field of semiconductor doping to the treatment of polymers and flexible substrates. It still continues to extend its use to other material classes and applications, and is becoming of interest for an increasing number of users. In this review we present a short, but comprehensive and consistent picture of the current state-of-the-art of FLA, sometimes also called pulsed light sintering. In the first part we take a closer look at the physical and technological background, namely the electrical and optical specifications of flash lamps, the resulting temperature profiles, and the corresponding implications for process-relevant parameters such as reproducibility and homogeneity. The second part briefly considers the various applications of FLA, starting with the classical task of defect minimization and ultra-shallow junction formation in Si, followed by further applications in Si technology, namely in the fields of hyperdoping, crystallization of thin amorphous films, and photovoltaics. Subsequent chapters cover the topics of doping and crystallization in Ge and silicon carbide, doping of III–V semiconductors, diluted magnetic semiconductors, III–V nanocluster synthesis in Si, annealing of transparent conductive oxides and high-k materials, nanoclusters in dielectric matrices, and the use of FLA for flexible substrates.