In 2021, the Titus Brandsma Institute and Radboud University in Nijmegen organized an international conference to mark the 550th anniversary of the death, on 25 July 1471, of Thomas a Kempis (b. 1379/80), the author of De imitatione Christi. This volume gathers the fruits of that meeting. Its aim is to contribute to the study, both of Thomas's works and the context in which he wrote them, and of their reception and appropriation throughout the centuries. Topics addressed include the mystical parallels and perspectives of Book III of the Imitatio, Thomas's development as a mystagogue and his methods as a hagiographer, the manuscripts that survive of his works at various libraries in Saint Petersburg, the story his relics, the influential German translation of the Imitatio by Johann Michael Sailer (1751-1832), and the way in which the inclusion, from the seventeenth century onwards, of increasing numbers of liturgical paratexts in Catholic editions of the Imitatio gradually turned these into books for church. The volume ends with an exploration of the views of St Titus Brandsma (1882-1942) on the Modern Devotion, which provide a useful basis for a more nuanced understanding of the Imitatio's seeming anti-intellectualism.