This chapter provides the essential concepts of classical mechanics required for understanding the classical charged particle beam optics. All charged particle beam devices, from low energy electron microscopes to high energy particle accelerators, are designed and operated very successfully on the basis of classical mechanics though the beams propagating through them are beams of microscopic particles, like electrons and protons, which should be obeying quantum mechanics. To understand this deeply, the quantum mechanics of charged particle beam optics is studied in detail in this book. This chapter gives an introductory review of classical mechanics just at the level necessary for understanding the classical charged particle beam optics. In particular, the classical mechanics of a single charged particle in an electromagnetic field is described in detail in terms of the Hamiltonian formalism.