Particle physics is the science that pursues the age-old quest for the innermost structure of matter and the fundamental interactions between its constituents. Modern experiments in this field rely increasingly on calorimetry, a detection techniques in which the particles of interest areabsorbed in the detector. Calorimeters are very intricate instruments, their performance characteristics depend in subtle, sometimes counter-intuitive ways on design details. This book, written by one of the world's foremost experts, is the first comprehensive text on this topic. It provides afundamental and systematic introduction, in which many intriguing calorimeter features are explained. It also describes the state of the art, both for what concerns the fundamental understanding of calorimetric particle detection and the actual detectors that have been or are being built andoperated in experiments. In the last chapter, some landmark scientific discoveries in which calorimetry has played an important role are discussed. This book summarizes and puts into perspective work described in some 600 scientific papers, listed in the bibliography.