This book shows how basic physical principles can be applied to describe interactions between living organisms and their microenvironment. Emphasis is placed on teaching the student how to calculate actual heat and mass transfer rates, rather than just studying the concepts involved. Numerous examples are provided to illustrate many of the principles, and problems are included at the end of each chapter to help the student develop skills in using the equations and to gain an understanding of modern environmental biophysics. The book is an engineering approach to environmental biology.