This course is designed for level 400 undergraduate Physics students. The main objectives of the course include describing simple structures in terms of a lattice and unit cell, understanding the cohesive energy between these structures and outlining how they may be determined. The course also treats basic features of coupled modes of oscillation of atoms in crystal lattice using the one-dimensional chain as a model and relates crystal properties (specific heat, thermal conductivity) to the behavior of these oscillations. The free-electron model and how it provides an explanation for many features of metallic behavior is also revised. The course also explains the basic features of semiconductors and relates this to simple semiconductor devices.