A previous version of these notes in French was circulated between 1988 and 1991 under the name: "Initiation au lambda-calcul". It formed the notes of a graduate course for the "DEA d'Informatique Fondamentale" at Université Paris VII. The next version formed the lambda-calculus portion of a course on Functional Programming given by the author at the Computer Science Division of AIT, Bangkok (Thailand), in 1992. The support of AIT is gratefully acknowledged. An update was prepared for the "Ecole Jeunes Chercheurs du Greco de Programmation'', Bordeaux, April 1992, and revised as notes for a course on lambda-calculus for the DEA Informatique, Mathématiques et Applications, taught at ENS in Paris during Fall 1992 and 1993, and for the DEA Fonctionnalité et Théorie des Types, Université Paris 7 in 1994. The present version was prepared for the DEA d'Informatique de l'Université Bordeaux I in 2002. It will be taught in 2004 in the course "Calculs Algébriques et Fonctionnels" of the MPRI (Mastère Parisien de Recherche en Informatique).