A bolometer is a sensitive electrical instrument for measuring radiant energy. Infrared detectors and related technologies have important applications not only in defense sector, but also for distinct civilian purposes. Some cost effective modern devices based on infrared technologies have been rapidly emerging on the global front. Different facets of bolometer advancements have been described in this book. It encompasses materials used, types of bolometers, their performance, utilization and prospective trends. This book will be of great help not just to the experts and professionals but also to the students who are involved in this discipline of science.