This Chapter presents the fundamental concepts of vehicle dynamics, in a rigorous yet relatively brief fashion. Bearing in mind the lack of unanimous conventions and stressing the need to fully control the hypotheses behind any model, formula or reasoning, this Chapter presents the three constituents of any (full) vehicle dynamics model: constitutive equations (tire model), congruence equations (kinematics), equilibrium equations (rigid body dynamics). Then, further insights and practical considerations are provided on a bunch of relevant aspects, including: radius of curvature (often misunderstood), sideslip angle (often not investigated with adequate depth), classical—and novel—perspectives on understeer and steady-state handling behavior.