The book is a clear and elementary presentation of the private theory of relativity, allowing a layman to correctly understand its main ideas and conclusions. The physical foundations of the theory, its most important formulas, laws and applications are illuminated in an intelligible form (without higher mathematics), but in sufficient detail and strictly scientific. Much attention is paid to explaining paradoxes and frequently asked questions: "Is it possible to get younger on the way?," "Is it possible to fly into the future?," "Is there a curve shorter than a straight line?," "Is it possible to cause?," "Is it conceivable to move faster than light?" etc.