Many single photon detection systems are based on the technology of superconducting nanowires. But despite their high detection efficiency, the need of cooling them to cryogenic temperatures prohibits their widespread usage. This book shows the progress of integrated (thick) CMOS SPADs towards high photon detection probabilities and applications such as in low-cost consumer data communication and high-end single-photon counting for quantum applications. Newest research results are introduced and comprehensively detailed.