This Brief presents a new way of introducing relativity theory, in which perplexing relativistic effects such as time dilation and Lorentz contraction are explained prior to the discussion of Lorentz-transformation. The notion of relativistic mass is shown to contradict the spirit of relativity theory and the true significance of the mass-energy relation is contrasted with the popular view of it. The author discusses the twin paradox from the point of view of both siblings. Last but not least, the fundamentals of general relativity are described, including the recent Gravity Probe B experiment.

Péter Hraskó received higher education in the Ural State Technological University in Yekaterinburg (former Sverdlovsk in USSR) and Ph. D. degree in physics in the KFKI Research Institute for Particle and Nuclear Physics in Budapest (Hungary). He worked there until his retirement. He was also professor of the Theoretical Physics Department at the University of Pécs (Hungary). Péter Hraskó received the Prometheus Medal of the Hungarian Society of Physics for the Spreading of Scientific Knowledge.

From Time Dilation to E = mc^2.- The Lorentz Transformation.- General Relativity.- Concluding Remarks.- Selected Problems