Dr. O. Rescher is one of the most industrious of Arabic scholars, and in the last few years he has done a large amount of valuable work. During a prolonged residence in Constantinople he devoted his attention to the libraries of Stambul, and he has published descriptions of a large number of the most important manuscripts, especially those relating to poetry, philology, and belles lettres. His descriptions, which form an important contribution to Arabic bibliography, are to be found in various periodicals, such as the Zeitschrift der Deutschen Morgenlandischen Gesellschaft, the Rivista degli Studi Orientali, Le Monde Oriental, the Mélanges de l'Université St. Joseph à Beyrouth, and the Wiener Zeitschrift fur die Kunde des Morgenlandes. It is scarcely necessary to say that these descriptions have made known to European scholars not a few works the existence of which would otherwise have remained unsuspected. Bibliography, however, is by no means the only branch of learning which has benefited by the activity of Dr. Rescher.