Health is maintained by the coordinated operation of all the biological systems that make up the individual. The Introduction to this 2nd edition presents an overview of what has been discovered by scientists regarding how bodily systems respond to environmental challenges and intercommunicate to sustain health. The book touches on the main findings from the current literature without being overly technical and complex. The result is a comprehensive overview of psychoneuroimmunology, which avoids oversimplification, but does not overwhelm the reader. Single authored for consistency of breadth and depth, with no redundancy of coverage between chapters. Covers endocrine-immune modulation, neuro-immune modulation, and the enhancing or inhibiting processes of one or more systems on the others. Expanded use of figures, tables, and text boxes. Online test bank for professors.