The relationship between music and religion has long been a clearly delineated one. Up to the late Middle Ages, music employed for ritual expressions of faith in sacred contexts was contrasted with secular music, then mostly played in open spaces. The former was believed to aid in the communication of divine truths, while the latter was suspected of arousing sensuality and thus potentially leading away from the spiritual perspective of life. In subsequent centuries, music entered first the courtly salons, then the concert hall and the home. Such music, created for virtuoso performance or for the enjoyment in private chambers, occasionally made room for an expression of religious experiences outside the dedicated spaces of worship. This aspect is particularly intriguing in instrumental music, where allusions to extra-musical messages are at best hinted at in titles or explanatory notes, and in those cases of vocal music where it can be shown that the musical language adds significant nuances to the verbal text. On the basis of various case studies that transcend a music-analytical approach in the direction of the hermeneutic perspective, this volume explores in which ways the musical language in itself, independently of an explicitly sacred context, communicates the ineffable. The discussion focuses on the musical means and devices employed to this effect and on the question what the presence of religious messages in certain works of secular music tells us about the spirituality of an era.