The compilation of a common listing of the serials holdings of the main astronomy libraries in the UK was proposed at the first Meeting of Astronomy Librarians of the UK held at the Institute of Astronomy in Cambridge in March 1980. The Library of the Royal Observatory in Edinburgh was at that time already engaged in a project to catalogue its serials holdings and at the same time to compile a separate, briefer, computerised listing for use in the library. Although the original idea had been that the proposed union list should record only the astronomy serials held by the participating libraries, the Royal Observatory Library offered to assume responsibility for the project as a natural development of its own list and to construct a union list that would record the complete serials holdings of all the participating libraries as it was felt that this would be of even greater benefit to these libraries.