Thermal images are essential to deal with situations in dark environments, as the thermal imaging theory is based on capturing the objects’ temperature. In Chapter One, the authors extract different features from images, which capture various characteristics of the images. Chapter Two discusses the use of hand held thermal imaging cameras for the use in Missing Persons searches. Chapter Three aims to review various infrared thermographic methods, viz., dynamic and steady state, passive and active methods for the detection of malignant lesion in breast and skin. Chapter Four is a review of literature regarding the relations between body composition and skin surface temperature (SST), measured with infrared thermography. Chapter Five discusses the use of infrared thermography in the medical field, and how the technique has the advantages of being non-invasive, fast, reliable, capable of producing multiple recordings in short intervals, and absolutely safe for patients and clinicians.