Building services is not a theoretical academic subject. It is a living, developing field of endeavour which touches everyone's lives. You are probably reading this in a heated (or air conditioned?) room right now! This book reflects the closeness between the academic study of building services with its practical application in its format. A traditional textbook is presented on the right hand pages and additional details including information on commercially available products and their suppliers is given on the left. By linking the theoretical descriptions with systems which can be seen around us in everyday life learning will be enhanced.