A systematic treatment, based on Green's functions and integral equations, is given to the analytical and numerical methods and results for a great number of 3-D contact problems for elastic bodies. Semi-bounded elastic bodies (layer, cylinder, space with cylindrical or spherical cavity, 3-D wedge, special cases of which are half- and quarter-spaces, cone) and finite elastic bodies (circular plate, finite cylinder, spherical layer, spherical lens, sphere) are considered. Methods introduced in the book can also be applied in fracture mechanics, hydrodynamics, electrostatics,...