This book embodies 20 letters professor Yuan Longping wrote to his student Dr. Mao Changxiang in the 1980s and 1990s. Professor Yuan Longping, internationally known as the “Father of Hybrid Rice”, had developed the first hybrid rice varieties in the 1970s and helped alleviate famine and poverty around the world. In the late 20th century, when the communication means were not yet developed enough, professor Yuan wrote a lot of letters to Dr. Mao Changxiang, the researcher of Hunan Hybrid Rice Research Center at that time, to discuss about the development of hybrid rice research. These letters were written in Chinese or English, most of which are originals and have not been published before and therefore are very valuable documents in the history of hybrid rice research.