Biosensors bring together the seemingly incompatible worlds of molecular biology and electronics. The function of a biosensor is to recognize the existence of a specific chemical in a solution or a mixture, and produce a signal that is related to the concentration of that chemical in the solution. The potential for applications of biosensors is enourmous and ranges from measuring oil pollution in the oceans to glucose levels in blood. This book introduces the molecular biology and biochemistry which underpins biosensor technology, before going on to describe the various types of biosensors and their applications, both scientific and commercial. The book will therefore be a useful guide to students and professionals from a wide range of life sciences disciplines with an eye to the exciting possibilities for future development of biosensor technology.