In this course, the mechanical behavior of structures and materials will be systematically introduced. It is expected that, after finishing this course, the students should have an overall understanding of mechanical behavior of materials, from the continuum description of properties to the atomistic and molecular mechanisms that confer those properties to all materials. This course will cover elastic, plastic and viscoelastic deformation, the fracture and fatigue behaviors of materials including crystalline and amorphous metals, semiconductors, ceramics, and polymers, etc. The techniques on the design and processing of materials from the atomic to the macroscale to achieve desired mechanical behaviors will be emphasized.