The Prometheus Trust has published exemplary editions of ancient philosophical texts, many of which were influential upon Renaissance magic. Among these were the neo-platonists, Including Iamblichus, who was notable for emphasising ritual and religion, i.e. theurgy.
The Platonic Commentaries complement his De Mysteriis as the core text laying out his views (see Finamore). John Dillon's wonderful 1973 translation from the Greek is here re-edited with a new introduction by Dillon. It gives the English reader a clean, clear and sensitive experience of Iamblichus' Platonic Commentaries. It is preceded by Dillon's 65-page overview of Iamblichus' life and thought, and is followed by his detailed analysis on each comment, which takes up 180 pages. A gem.
Frome: Prometheus Trust, 2009. 450 pages, hardback. New.