Léon Boëllmann (1862–1897) studied at the École Niedermeyer and was titular organist at St-Vincent-de-Paul in Paris. In the tradition of Saint-Saëns, Franck and Gigout, his compositions reflect the elegant urbanity of the Belle époque.

Published in 1896, Heures mystiques is a collection of one-hundred short pieces for organ or harmonium offering organists a treasure-trove of easy compositions for use in church services. The appendix contains suggested alterations to the musical text as examples for imaginative renditions on multi-manual instruments.

- First complete Urtext edition of the works of Léon Boëllmann in six volumes
- Easy pieces for use in church services
- Based on the latest scholarship and newly discovered sources
- Detailed preface and critical report in French, English and German
- Facsimiles of previously unknown source material and catalogue of sources