Joseph Needham (1900-1995) is one of the greatest scholars of the 20th century with a very unique career. A biochemist, he is notably with Conrad H. Waddington, one of the founders of British chemical embryology. At the same time, J. Needham continues to intervene in other fields of thought and science (epistemology of science, philosophy, politics, history). Having always considered himself a scholar and a citizen, socialist and Christian, he became involved in political action within the English left from the 1920s. In 1937, following the arrival of young Chinese doctoral students in Cambridge, he began to take an interest in the Chinese world, and in particular in the sciences and techniques of this civilisation. During the Second World War, he led an official mission to help Chinese scientists, in the middle of the Sino-Japanese War. It was on this occasion that he matured a gigantic and unprecedented project: to make the history and analysis of all of the Chinese sciences, techniques and thought. The first volume of Science and Civilisation in China, written by Joseph Needham with the collaboration of Wang Ling, appeared in 1954; many researchers participated in this intellectual adventure; the last volume published dates from 2015. The interview was carried out between 1988 and 1989 in a few meetings and we discover the immense knowledge, originality, humour, mindedness of Joseph Needham.