The Harvard College Observatory will issue this summer a new series of nine popular books covering the principal areas of astronomy, it was announced today by Harlow Shapley, Paine Professor of Practical Astronomy, and Bart J. Bok, associate professor of astronomy, editors of the volumes.

The books will be titled "The Harvard Books on Astronomy," and are written by the Harvard Observatory specialists in the various fields. Five of the volumes are now in press, and the remaining four will be issued before fall.

The volumes will give a complete and simplified presentation of modern scientific knowledge in each of the major fields of astronomy, it was explained. They are designed for adults, and secondary school or university students, having acquaintance with the most elementary principles of physics. By separating the treatment into nine volumes, of about two hundred pages each, it will be possible to keep the series up to date by issuing new editions of individual volumes as scientific progress indicates, the editors explained.