This book introduces the basic knowledge, concepts, terms and development process of high-speed rail (HSR) and summarizes its main achievements at this stage. It mainly expounds the connotation of high-speed rail to readers from two different aspects of theory and technology. The book explains the development process of high-speed rail in terms of time: yesterday's wheel rail high-speed rail, today's maglev high-speed rail and tomorrow's super high-speed rail; and also spatially, making a comparative analysis of the development around the world.