Responding to the challenges of organizing the rapidly growing body of information caused by the development of printing, Johannes Trithemius (Tritheim), abbot of the Benedictine abbey at Sponheim, completed his manuscript for the earliest subject bibliography, Liber de scriptoribus ecclesiasticis (A Book on Ecclesiastical Writings) in 1492. It was the first bibliography compiled as a practical reference work. In 1494 the work appeared in Basel at the press of Johann Amerbach.
The work " lists in chronological order 982 authors with about 7,000 titles, the number of chapters in each work and the incipit when known. An alphabetical list, arranged according to the authors' first names, serves as an index. The title of the book is somewhat misleading since the work is not restricted to ecclesiastical writers but also includes authors such as Dante, Poggio, and Sebastian Brant" (Breslauer & Folter, Bibliography: Its History & Development  no. 7).
Tritheim's author index is unusually extensive for a 15th century book— in some ways a prototype of modern author indices except that it is by author's first name. Because Tritheim was writing a reference book for preachers he included selected literary works that he thought preachers should read.
"The contrast between the feeble theological bibliographies of the manuscript age and this first attempt in the printing era is very striking” (Besterman, The Beginnings of Systematic Bibliography 7-8).