The development of radiation detectors is closely entangled to the study of elementary particles and of their interactions. From the early observations of cosmic rays using photographic emulsions, to the present complex electronic systems operating in high-energy accelerators, this book describes the evolution of detectors employed in particle physics and astrophysics: cloud and bubble chambers, spark chambers, solid state and gaseous position-sensitive detectors. Major discoveries have been made making use of increasingly advanced devices: natural radioactivity, X-rays, π mesons, the positron, the W and the Higgs bosons, only to mention a few. Suitable for practitioners and students of particle physics, this book gives a concise but comprehensive description of the evolution and major applications of radiation detector technologies. Fabio Sauli received his PhD in Experimental Physics from the University of Trieste in 1965. He was a member of the research staff at CERN from 1969 until his retirement in 2006, during which he did work in the Gas Detectors Development (GDD) group initiated by the Nobel laureate Georges Charpak. Sauli was also the leader of the group since 1992. From 2006 to 2018, Sauli was associated with the TERA foundation (Fondazione per Adroterapia Oncologica). Presently, he is an Honorary Member of CERN and of the RD51-DRD1 Collaborations. Among his other accolades, Sauli has been awarded a Doctor Honoris Causa at the Université de Haute Alsace and received the ICFA Instrumentation Award in 2023. He has also been Adjunct Professor at Northeastern University in Boston and Bicocca University in Milano. Sauli has authored several books and hundreds of articles devoted to radiation detectors. Among his recent books are Micro-Pattern Gaseous Detectors , World Scientific (2021); Gaseous Radiation Detectors, Fundamentals and Applications , Cambridge University Press (2014). These books feature his original developments the Multistep Avalanche Chamber and the Gas Electron Multiplier. Sauli has also been Editor for the journals Nuclear Instruments and Methods in Physics Research (since 2000) and Instruments (since 2019).