Preface

Since the publication of the first edition of the Handbook of Olfaction and Gustation in 1995, advances in chemosensory science have been staggering. Indeed, during this period the chemical senses have become a central element of the field of modern neuroscience, largely because of their regenerative capacities, integral association with stem cell research, and unique transduction processes. As a consequence of the proliferation of commercially available olfactory tests, olfaction is now routinely and quantitatively evaluated in most major medical centers, as well as within the food, beverage, cosmetic, and energy (e.g., gas works) industries. Of particular relevance to the physician is the fact that decreased smell function is likely the first clinical manifestation of Alzheimer's disease (AD) and idiopathic Parkinson's disease (PD). Indeed, accurate assessment of olfaction can aid in the "preclinical" identification of individuals at risk for these disorders. Such assessment can also aid in differential diagnosis, since diseases often misdiagnosed as AD or PD (e.g., major affective disorder, progressive supranuclear palsy) are unaccompanied by meaningful olfactory loss.

The second edition of the Handbook represents the largest collection of basic, clinical, and applied knowledge on the chemical senses ever compiled in one volume, with contributions from over 80 of the world's leading researchers. The material in this up-todate treatise has been tailored to be of value to a wide range of medical specialists, as well as to basic scientists working in academics, industry, and government. Because the information is presented in a straightforward manner, this volume can serve as a textbook for graduate students, medical students, and postdoctoral fellows from numerous disciplines. The chapters are conveniently arranged into three major sections corresponding to olfaction, gustation, and other chemosensory systems and, with the exception of the last section, are subdivided into (A) anatomy and neurobiology, (B) functional measurement, ontogeny, and genetics, and (C) clinical applications and perspectives. Unlike the first edition, this edition contains an author index that makes it possible for researchers and others to quickly find references and sections based on individual contributions. As in the first edition, historical perspective and clinical relevance have been emphasized, but not at the expense of basic science. The book has been expanded from 38 to 48 chapters, so as to take into account major growth in a number of fields, including neuroscience, functional imaging, cybernetics, toxicology, structure-activity assessment, molecular biology, and animal behavior.

I am grateful to the contributors, who have been a model of objectivity and scholarship in the development of their chapters, and who have graciously taken into consideration my often extensive editorial suggestions and criticisms. I am also indebted to the staff of Marcel Dekker, Inc., particularly Jinnie Kim, Assistant Acquisitions Editor, and Ann Pulido, Production Editor, who have patiently and painstakingly worked with me to ensure a volume of the highest quality. Without the support of the following grants from the National Institutes of Health, this work would have never been accomplished: PO1 DC 00161, RO1 DC 04278, RO1 DC 02974, and RO1 AG 27496.