The book describes the fundamentals of particle detectors in their different forms as well as their applications, presenting the abundant material as clearly as possible and as deeply as needed for a thorough understanding. The target group for the book are both, students who want to get an introduction or wish to deepen their knowledge on the subject as well as lecturers and researchers who intend to extent their expertise. The book is also suited as a preparation for instrumental work in nuclear, particle and astroparticle physics and in many other fields (addressed in chapter 2). The detection of elementary particles, nuclei and high-energetic electromagnetic radiation, in this book commonly designated as ‘particles’, proceeds through interactions of the particles with matter. A detector records signals originating from the interactions occurring in or near the detector and (in general) feeds them into an electronic data acquisition system. The book describes the various steps in this process, beginning with the relevant interactions with matter, then proceeding to their exploitation for different detector types like tracking detectors, detectors for particle identification, detectors for energy measurements, detectors in astroparticle experiments, and ending with a discussion of signal processing and data acquisition. Besides the introductory and overview chapters (chapters 1 and 2), the book is divided into five subject areas: – fundamentals (chapters 3 to 5), – detection of tracks of charged particles (chapters 6 to 9), – phenomena and methods mainly applied for particle identification (chapters 10 to 14), – energy measurement (accelerator and non-accelerator experiments) (chapters 15, 16), – electronics and data acquisition (chapters 17 and 18). Comprehensive lists of literature, keywords and abbreviations can be found at the end of the book.