This expository treatment is based on a survey given by one of the authors at the Séminaire Bourbaki in November 1978 and on a subsequent course held at the University of Göttingen. It is intended to serve as an introduction to the topical question of classification of holomorphic vector bundles on complex projective spaces, and can easily be read by students with a basic knowledge of analytic or algebraic geometry. Short supplementary sections describe more advanced topics, further results, and unsolved problems. This is a corrected third printing with an Appendix by S. I. Gelfand. ------ The present book is the first one, within the extensive literature on algebraic vector bundles, to give both a self-contained introduction to the basi...