The book Types of Photodetectors and their Applications, edited by Dr. S. S. Kushvaha and Dr. V. N. Singh and published by Nova Science Publishers, Inc., USA, is the result of joint efforts of some well-known researchers in the field. The broad electromagnetic spectrum bands from ultraviolet (UV) to terahertz (THz) are effectively detected by PDs depending upon specific applications. Broadband PDs have various applications in various fields, i.e., security, defense, optical communication, imaging, bio-medical, night vision, environmental sensing, process control, etc. Thus, PDs are touching almost all aspects of life. The book comprises eight chapters and discusses various aspects of photodetectors, starting from multiple materials, configurations, methods to enhance its performance, etc. The book aims to cater to the need of budding researchers in the field of optoelectronics and post-graduate students.