After a brief introduction on his youth and education, the paper concentrates on the origin and importance of the work of Paul Sabatier (1856-1941). After his "docteur es sciences" thesis on sulphides in 1880 under the guidance of Marcellin Berthelot at College de France in Paris, and a very short stay at the University of Bordeaux to teach physics, he became Professor of Chemistry at the University of Toulouse from 1884 until he retired in 1930. Sabatier worked on different subjects (noteworthy is his book on agricultural chemistry) before concentrating on the subject which earned him the celebrity. The publications of Mond et al. (action of carbon monoxide on nickel) and of Moissan and Moureu (action of acetylene on nickel) are at the origin of the work of Sabatier and Senderens who discovered the method of direct hydrogenation of organic molecules on finely disintegrated nickel. The paper raises the question as to why the Nobel Committee did not use the word catalysis in the nomination concerning Sabatier. As a matter of fact, Sabatier not only used catalysts but also proposed the first chemical theory of catalysis based "on the temporary formation of unstable chemical compounds which, serving as intermediate steps in the reaction, determine its direction or increase its velocity". Among all the physical and chemical theories of catalysis proposed so far, that of Sabatier has undergone the test of time with success and still continues to be fertile. Paul Sabatier leaves a considerable legacy, not only locally (he is at the origin of three Schools of the Institut National Polytechnique of Toulouse) but also internationally (major contribution to the development of agricultural chemistry and industrial catalysis) and beyond, notably with the so-called "Sabatier" reaction ( CO2 + 4H(2) CH4 + 2H(2)O) currently used in the International Space Station to produce the water necessary onboard. (C) 2013 Elsevier B.V. All rights reserved.