This work, also known as Fervor Amoris , is a late-medieval devotional prose text. In essence it is a manual of guidance for the spiritual and ethical life, directed at the lay population, and intended for both sexes, rather than at a monastic audience (although there is evidence that the text was read by nuns). It is a useful index of English popular spirituality since its circulation seems to have been extensive: it survives in 16 manuscripts, dating from the early-to-mid 15th century, and two early 16th century printed editions, evidence of its enduring popularity into the Early Modern period. This critical edition of the text is based on one manuscript, with variant ratings cited from the other witnesses where necessary; the volume has a full critical apparatus, and an introduction which discusses manuscript relations, matters of textual criticism, editorial technique, language, and dating.