It is impossible to imagine today's Physics without the Theory of Relativity, just as it is impossible to envision it without atoms and molecules.

This theory changed our relationship with the surrounding world and is considered one of the most challenging topics for the general reading public.

The authors of this volume, globally renowned academics, Nobel and Lenin Prize winners, Professor Leon Davidovich Landau (1908-1968) and Professor Yuri Borisovich Rumer (1901-1985), guide us with their simplicity, communicativeness, and humor through the difficult yet exciting paths of modern Physics, taking slow and steady steps.

Modern Physics, with countless applications, has become an integral part of our everyday lives.