The present book gives definitions of the basic physical concepts and quantities studied in an elementary physics course, formulates physical laws, and briefly explains the essence of the phenomena they describe. Some chapters contain problems and their solutions.>The book is intended for a very broad circle of readers: secondary school pupils, students at vocational schools and special secondary educational institutions, and students Inking preparatory courses at institutes. It will be a great help to students preparing for entrance examinations to higher educational establishments. Having in mind people studying physics independently, the authors also included s o m e information on classical and modern physics that is beyond the scope of secondary school syllabi. These chapters and sections are marked with an asterisk. Attention is con­stantly given to the interpretation of the physical meaning of laws and the phenomena they describe. The mathematics needed to use the book is within the scope of a secondary mathematics course.