The textbook "Photoactive Semiconductor Nanocrystal Quantum Dots" from the series "Topics in Current Chemistry Collections" provides a comprehensive overview of the latest developments in the field of photoactive semiconductor nanocrystals. It is aimed at a broad audience, including professionals from industry and academia who are interested in the intersections of chemistry, biology, medicine, and materials science. The contributions in this volume are designed to not only highlight the key advancements of the past five to ten years but also to make the underlying principles and methods understandable. The critical reviews offer valuable insights into current research topics and their relevance for future developments in this dynamic research field.