Once upon a time, there was a single journal, The Physical Review. It was a small journal, and the editorship was a part-time job for a university professor. The papers in it were rather discursive, and they were printed with generous line spacing and margins, in a format not too different from today's Il Nuovo Cimento or Nuclear Physics, and they could be easily read and thus better understood.But the physicists of the day felt that something else was needed: some sort of vehicle for short notes that would either deal with a significant but small point or give advance notice of some important new development. To meet this need, a "Letters to the Editor" section was added to The Physical Review. By limiting that section to very short papers and by eliminating sending proofs to the author, the publishers were able to print "Letters" sooner after receipt than regular Articles. But it was a more leisurely time, and nobody seemed to be under great pressure to get his work communicated rapidly, and the Letters section grew at a pace about like the rest of the journal.By about fifteen years ago, things had changed. There was now a great urge to publish quickly; and the Letters section soon became overloaded. The remedy that seemed most reasonable was to impose a requirement of urgency that was to be satisfied by any paper accepted as a Letter. This concept was retained in 1958 when the "Letters to the Editor" section was split off to form a second journal, Physical Review Letters.The big trouble is, and has always been, what constitutes urgency. One approachis the statement on our masthead: "...important new discoveries or topics of high current interest in rapidly changing fields of research." Another is a phrase we offered several years ago: "...likely to have an immediate impact on the work of a substantial number of others." As one referee puts it, "To what extent is the result going to change our current views on a subject? Will it change the programs of other workers in the field? The interpretation of their results?"The problem is perhaps especially severe in regard to theoretical papers. Here we have recently had what we regard as an exceptionally clear statement from a referee, which we quote:I regard a theoretical communication as urgent only if it satisfies one or more of the following criteria in addition to originality: (1) It states and solves an outstanding basic problem or calls attention to a new area of research. (2) It presents a new method which might enable physicists to solve other important problems. (3) The implications of the work have immediate impact on current experimental activity, either by suggesting a new method for analyzing data or by suggesting new experiments for which plans should be made immediately.We regard these as very reasonable criteria, and we hereby ask our referees to apply them. There will still be subjectivity in judging whether they are met, but this is unavoidable. We still expect that their use will result in an improvement in the quality of our journal.