This Chapter focuses on the geometry of motion (Kinematics) and deformation of a continuum. Particular attention is given to the theory of deformation of a solid material in which the displacement field of the solid material is defined relative to the undeformed state (or reference configuration) of the material. The concepts of displacement gradient, finite strain tensor and infinitesimal strain tensor are then introduced and the geometrical aspects of strain are examined for two and three dimensional continuum systems. The Chapter concludes with the consideration of the transformation of the strain tensor to its principal coordinate system. The Example problems illustrate how the displacement gradient, infinitesimal strain tensor and principal strains are computed from a given displacement field of a solid.