This is a 20-volume series published from 1959 to 1962, but volume 5 is missing. This set consists of 19 volumes (volumes 1-20, excluding volume 5), all first editions. The monthly bulletins are included for all volumes except volume 5. There is some staining, yellowing, and soiling due to aging. Some of the cases have damage. The original paper wrappers have tears, some are missing, and some are intact. Severely torn wrappers have been temporarily covered with glassine paper. There are no markings or writing, and the books are readable. Please forgive any oversights. Please consider this as a used book.