John G. Ryden and Yale University Press

Yale University Press is housed in a former chapel on the edge of its Ivy League campus. Although the offices are in a quirky building, the press operations run smoothly. Numerous passages and stairways lead to small offices, each decorated to fit the tastes of its occupant. In alcoves of the high-ceilinged former chapel, copy editors edit, while workmen and packing crates portend the installation of a computer system.

In staffing, premises, and its catalog, Yale University Press blends old and new to issue highly respected books for scholars.

John G. Ryden, who came to Yale in 1979 with a career in trade and university press publishing, sees the role of a university press to be twofold: ''to publish what otherwise could not be published,'' and ''to treat the works in a special way.''

''The essential part of our mission,'' says Mr. Ryden, ''is to make it possible for the scholar to publish his very first book. We expect to do that and to publish the kinds of books that represent many years of labor but have a tiny audience. We also give our books the care and attention that they must have before they can be published, including careful editing and attention to detail. Then we ensure that they will be produced on paper that will outlive the libraries and that they will be kept in print for many, many years.'' He smiles, ''We do this not without regard to how much it costs, but with an eye that must first of all deliver a book of the highest quality and then hope to God that the institution can survive that!''

Yale's offerings cover a broad range under the rubric ''scholarly,'' from monographs to editions of primary sources, reference works and educational materials, to works of synthesis or interpretation: scholarship that goes beyond reporting to other specialists in the field and has an audience of scholars and informed general readers.

At present, this type of book stirs the most interest at Yale. ''A few years ago,'' Ryden explains, ''we were doing two or three, or four, of these books a season - up front in the catalog, as it were; now we're doing as many as 10 or 12. We are looking for this kind of book more aggressively as we are increasingly able to step into an arena that was once the purview of trade houses.''

The lead title in Yale's Fall 1984 catalog is ''The Chronicle of the Lodz Ghetto, 1941-1944,'' which documents the ''liquidation'' of the Jewish ghetto in Lodz, Poland. It was important to the editor, Lucjen Dobroszyck, himself a survivor of Lodz, that the book be handled sensitively and marketed as an accurate document, rather than as an exploitation of horror.

When books like this sell well, they help support less profitable titles. But Ryden stresses that paperbacks and reference books can also be gainers. As an example, he pulls down two volumes from his shelf. They are Huffman and Proum's ''English-Khmer Dictionary,'' a work that reflects Yale's strengths in languages. ''We expected it to sell 500 copies when we published it in 1978. It eventually sold 15,000. It amazed us. It delighted us!'' Ryden beams.

Another profitmaker is ''A Handbook of Clinical Dietetics.'' ''Practicing dieticians simply must have it,'' he explains. Ryden is looking forward to filling another gap in scholarship with a handbook of Russian literature to be issued in the spring of 1985.

Ryden, who is ''an editor by inclination, training, and instinct,'' guides a staff that chooses manuscripts for their contribution to knowledge.