This book is a comprehensive study of the life and mathematics of Walter Noll, who helped to create the mathematical tools of modern rational mechanics and thermodynamics. Noll is one of the brilliant mathematicians of the second part of the 20th century. His contribution is large in both the applied and pure mathematics. The book stresses particularly Noll's method of axiomatization of physical theories, his axiomatics of continuum mechanics, thermodynamics of materials, special relativity theory, his discovery of the neo-classical space-time of mechanics, his theories of inhomogeneities in simple bodies, fit regions, contact interactions, annihilators of linear differential operators, and finite-dimensional spaces. It is a must for every mathematician, physicist, engineer or graduate student as a reference and key to Noll's mathematical heritage.