When Imre Lakatos died in 1974, many friends and colleagues expressed the hope that his unpublished papers would be made available. Some were also interested in seeing his contributions to journals and conference proceedings collected together in a book. At the request of the managing committee of the Imre Lakatos Appeal Fund we have prepared two volumes of selected papers which we hope will meet these demands.

None of the papers published here for the first time was regarded by Lakatos as entirely satisfactory. Some are early drafts, while others seem not to have been intended for publication. We have pursued a fairly liberal policy, including papers which, at least in their present form, Lakatos would not have allowed to go to print. As for previously published papers, we have included them all except for the two papers, ‘The Role of Crucial Experiments in Science’ and ‘Criticism and the Methodology of Scientific Research Programmes’, which would have introduced undue repetition, and except for Proofs and Refutations, which recently appeared in book form.

Volume 1 is a collection of Lakatos's best known articles developing the methodology of scientific research programmes, together with a hitherto unpublished essay on the effect of Newton's scientific achievement, and a new ‘Postscript’ to the already published paper on the Copernican Revolution.

Although Lakatos perhaps came to be better known for his work in the philosophy of the physical sciences, he regarded himself as primarily a philosopher of mathematics.