Mechanics is a branch of Physics that deals with scientific analysis of motion, time and forces. It is divided in two parts: statics and dynamics. Statics studies the equilibrium conditions of stationary systems (not taking motion into account). On the other side, dynamics studies moving systems that change with time and the forces acting on them. At the same time, dynamics is divided up into kinematics and kinetics. Kinematics analyzes the movement of bodies without considering the forces causing such motion while kinetics takes those forces into account. In this chapter we will describe the basic definitions that will help us to predict the kinematic behavior of a given mechanism as degrees of freedom, links and kinematic pairs, classification of kinematic pairs, kinematic chain, mechanisms, kinematic skeleton and machine, classification of link movement, kinematic inversion, Grashof’s criterion, mechanical advantage and kinematic curves.