Abstract
This chapter reviews the laws governing the friction behavior of objects. The material starts with a historical view of the evolution of friction laws and how they shaped the science of tribology. The second part of the chapter provides a generalized overview of the mechanics of contact between complying solids. Major contact models are listed, and formulas for calculating area of contact, contact forces, contact stresses are also developed. Finally, the chapter applies the presented information to the contact of biological species. The information presents a summary of the major rules in biological attachments, their adhesion and friction, along with their contact mechanics.