Many advances have been made in the field of thermoregulation in the past few years. These include our understanding of Fever, which is now considered not simply a rise in deep body temperature foHowing infection, but just one aspect, though perhaps the most easily measured, of the Acute Phase of the Immune Response. Classification and identification of the Cytokines and the availability of recombinant material has greatly aided this research. Similarly, our understanding of the Hypothalamo-Pituitary Adrenal Axis has altered our way of thinking about temperature regulation. Of importance are the problems associated with adverse climatic conditions and survival, and the problems encountered by the neonate and the hibernator. At the biochemical level, our knowledge of the control of heat production and the role of brown adipose tissue is rapidly advancing. All these issues and many others were discussed at a Symposium 'Thermal Physiology 1993' held in Aberdeen, Scotland in August 1993 under the auspices of the Thermal Physiology Commission of the International Union of Physiological Sciences. Six main aspects of the subject of temperature regulation are included in this book, namely, Fever (including the Acute Phase of the Immune Response and Thermoregulatory Peptides), Neurophysiology of Thermoregulation, Neonatal Thermoregulation, Mechanisms of Heat Production, Ecological and Behavioural Thermoregulation, and Emerging Themes in Thermoregulation.