Infra-red thermal imaging is a rapid and non-invasive procedure for mapping skin temperature distribution of the human body. The natural infra-red emission from the skin is captured by the imaging camera, and is displayed as a digital image. Advanced software and high resolution infra-red detectors has allowed for a renaissance in the use of infra-red thermal imaging or thermography in medical research and practice. Thermal imaging provides a two dimensional map of skin temperature, which can often indicate a localisation of hypo or hyperthermia and its major clinical value is in its high sensitivity to pathology in the vascular, muscular, neural and skeletal systems and as such can contribute to the pathogenesis and diagnosis. After a brief review of theory and technology of infra-red imaging the bulk of the book consists of a collection of clinical case studies demonstrating the wide variety of applications for thermography in modern medicine. The combined expertise from a number of centres is used to create a database of images that will be invaluable for practitioners in making diagnoses and measuring treatment efficacy.