This pedagogical monograph describes some of the fundamental laws of physics. The derivations are, however, obtained from a rather unconventional point of view. The Lorentz transformations and the special theory of relativity are derived without mentioning the phenomenon of light, and the de Broglie relations in the wave–corpuscle parallelism are derived without the help of Planck's constant. By the use of Schrödinger's idea of “quantization as an eigenvalue problem”, the foundations of wave mechanics are discussed as a mathematical problem without reference to Planck's constant. Finally, the Kepler problem in the special theory of relativity is studied starting from the energy law, and the applications to the Hulse–Taylor binary pulsar indicate that more data about the unseen companion are needed before the interpretation of the present data may be taken as the ultimate proof of the validity of the general theory of relativity.