There has been a virtual explosion of scholarly writing on Jewish history in the medieval and modern periods during the last thirty years. One rough measure of this development is to compare the present entries on Jewish history in this Guide with the previous edition published in 1961. Of the hundred and twenty items on Jewish history listed in the earlier Guide, less than half actually pertain to the medieval and modern periods. This compares with some 325 items allotted to this section of the present Guide dealing exclusively with postancient Jewish history. But the sheer number of cited works is only the beginning of the story. Among the entries in the 1961 edition, the number of individual authors is relatively small; Salo W. Baron is listed several times, as are Cecil Roth, Jacob Marcus, and Guido Kisch. This obviously reflects the relatively small number of professional historians in the field as of 1961 and an even smaller number holding full-time positions in North American universities.