The document provides an overview of x-ray crystallography techniques used to determine protein structures. It discusses the historical background, principles of x-ray crystallography, why crystals are needed, how proteins are purified and crystallized, how crystals are tested and data is collected, and how the structural solution is determined through model building and refinement. The key steps involve growing protein crystals, collecting diffraction data from crystals, using the data to solve the phase problem and visualize electron density maps to build atomic models.