Gerlach Peters (d. 1411) was a member of the so-called Devotio moderna. In the second half of the fourteenth century this religiuos reform movement arose in the Northern Netherlands, and strove after spiritual renewal for everyone. Its influence on the religious life of Northwestern Europe was considerable. Its most famous member was of course Thomas a Kempis. Gerlach Peters was a contemporary and colleague of Thomas. He is considered as the most important mystical author of the Devotio moderna. We dispose of two middle Dutch letters and two Latin works, Breuiloquium and Soliloquium. His Soliloquium was widely read in the Middle Ages, and it has been reprinted and translated up until today. This is the first critical edition of Gerlach Peters' Opera omnia, based on 72 extant manuscripts. The Middle Dutch letters are accompanied by a modern English translation, whereas the medieval translations of the Latin text have been critically edited. The book also contains an introduction, in which the life and work of Gerlach are treated. Attention is paid to the existing printings, reception and text history, genre and literary-historical aspects. In this book historians, theologians, medievalists and philologists will find new materials for the study of the religious life in Northwestern Europe in the fifteenth century. (Publisher's information). 'Mikel Kors is to be congratulated for his impressive achievement. One can only hope that it will encourage subsequent editions of the literature of the Devotio Moderna as well as a renewed examination of the religious mentality reflected in its works.' (O. GRÜNDLER in: Speculum, 2002, pp.973-975).