Book excerpt: 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, thermodynamics and diffusion theory, continuum mechanics, and mathematical physics, as well as by engineers and students in mathematics, mechanics, and physics.