of ancient literature, both sacred and classic, are valuable and have been "recovered" or restored by the use of chemical reagents coupled with the all but infinite patience of the decipherers. A commentary of the Psalms by Augustine, written over Cicero's "De Republica," and a treatise of little value by a Syrian monk, Ephraem, superimposing a valuable fifth century manuscript of the New Testament, are examples of palimpsests in classic and Biblical literature. Some of the writings of Livy and certain books of Pliny the Younger have been recovered from superimposed writings of little or no historical value. Two facts concerning the change in the form of manuscript books are demonstrable: (1) That the first books were "rolls" or "volumes"; and (2) that, early in the Christian Era, books of "leaves" had come into relatively common use. It is not an insignificant fact that the earliest manuscripts in the form of books with leaves show the largest number of columns to a page--approximating thus more nearly the continuous columns of the earlier "roll" book. In other words, the earliest and best known of the Greek manuscripts of the Bible--the manuscripts which are most relied upon by the scholars for all critical, scriptural study--the codices known, respectively, as the "א," or the Sinaitic, treasured at Petrograd; the "B," or the Vatican, kept at Rome; the "A," or the Alexandrian, deposited in the Manuscript Room of the British Museum; and the "C," or the Ephraem, the famous "palimpsest" preserved in the National Library at Paris (all of them written in the fourth and fifth centuries) are "books" of leaves--the one most similar to the ancient "roll" book in form and arrangement of the pages being, presumably, the oldest.