The intuitive understanding of contact bodies is based on the geometry and adjoining surfaces. A powerful approach to solve the contact problem is to take advantage of the geometry of an analyzed object and describe the problem in the best coordinate system. This book is a systematical analysis of geometrical situations leading to contact pairs: suface-to-surface, curve-to-surface, point-to-surface a.s.o. resultingin the corresponding computational algorithms to solve the contact problem.