The book "Semiconductor Laser Fundamentals" offers a comprehensive introduction to the fundamentals of semiconductor laser technology. It addresses the significant developments and advancements that have been made since the manuscript was published in 1993. The authors, Weng W. Chow and Stephan W. Koch, illuminate the various laser and amplifier structures used in modern semiconductor laser technology, including the vertical-cavity surface-emitting laser (VCSEL) and the monolithic master oscillator power amplifier (MOPA). The book discusses the critical dependence of device performance on the properties of the gain medium, such as spectral shape and carrier density. Additionally, new material systems are introduced, spanning from mid-infrared to ultraviolet emission, which are important for a variety of optoelectronic applications. The authors also discuss the differences between novel semiconductor laser materials and conventional systems, particularly regarding band structure modifications and Coulomb effects.