Amazing as it may be, to this day few commentaries on the treatises of Plotinus' Enneads are written. The classic ninth treatise (VI,9 in Porphyrius' order), for example, has hardly been studied. This treatise, however, is of vital importance, because it is in this work that for the first time in the Enneads, the One in its superform emerges and Plotinus dwells on the remarkable phenomenon of a 'mystical union' of the soul with the One. A thorough analysis of the argument and its development next to philosophical and philo-logical support will be welcome to any reader of this in-triguing but...