Gerhard‹s book of prayer was published in 1612 for the first time in Latin. There were 86 editions of this work, it was translated into 13 languages and had an international and interdenominational impact. This edition provides a parallel version of the Latin text and the contemporary German translation. The text is made accessible by text-critical annotations and evidence of biblical quotations as well as references to ancient Christian and medieval sources. The appendix contains all of the spiritual songs which the Szczecin pastor Friedrich Fabricius (1642–1703) included in his new edition of the ‹Exercitium‹ from the year 1688. There is also an introduction to the origins and the impact.