Any interactions between two protein molecules enabled by electrostatic forces like hydrophobic effect is known as protein-protein interaction. The examples of these interactions are cell metabolism, signal transduction, muscle contraction, transport across membranes, etc. The process is used in many subjects namely quantum chemistry, molecular dynamics, biochemistry, etc. This book is a compilation of chapters that discuss the most vital concepts in the field of protein-protein interactions. It discusses in detail the various applications and techniques of the subject. For someone with an interest and eye for detail, this textbook covers the most significant topics in this field. It will serve as a reference to a broad spectrum of readers.