X-Rays -- Diffraction of X-rays -- Crystals, symmetry, and space groups -- Crystals and their properties -- Geometric data collection -- Intensity data collection -- Data reduction -- Theory of structure factors and fourier syntheses -- Calculation of structure factors and fourier syntheses -- The phase problem -- Direct methods -- Patterson methods -- Heavy atom methods -- Search methods -- Completing the structure -- Refinement of crystal structures -- Random and systematic errors -- Derived results -- Ambiguities and uncertainties.