I.M.Gelfand, one of the leading contemporary mathematicians, largely determined the modern view of functional analysis with its numerous relations to other branches of mathematics, including mathematical physics, algebra, topology, differential geometry and analysis. With the publication of these Collected Papers in three volumes Gelfand gives a representative choice of his papers written in the last fifty years. Gelfand's research led to the development of remarkable mathematical theories - most now classics - in the field of Banach algebras, infinite-dimensional representations of Lie groups, the inverse Sturm-Liouville problem, cohomology of infinite-dimensional Lie algebras, integral geometry, generalized functions and general hypergeometric functions. The corresponding papers form the major part of the Collected Papers. Some articles on numerical methods and cybernetics as well as a few on biology are included. A substantial part of the papers have been translated into English especially for this edition. This edition is rounded off by a preface by S.G.Gindikin, a contribution by V.I.Arnold and an extensive bibliography with almost 500 references. Gelfand's Collected Papers will provide stimulating and serendipitous reading for researchers in a multitude of mathematical disciplines.