Just concluded a pair of introductory philosophy courses wherein I used Ed Feser's Aquinas as a required text. Here's my Amazon review:
Two Mints in One
Not only is this the best introduction to the thought of Aquinas that you're ever likely to find, but it's also a superb primer on the metaphysics of Aristotle. Act & potency, form & matter, the four causes...they are all explained here about as clearly & simply as they can be.
When teaching philosophy, I prefer to use original texts. But it's not always possible - especially in introductory courses. Some of the greatest philosophers were also great communicators: Plato, Descartes, Hume, Nietzsche, & William James are among the names that spring to mind. But not all were: Aristotle, Aquinas, Spinoza, Kant & Hegel, among others, are notoriously difficult, without a Vergil to guide one from one hellacious circle to the next.
For Aristotle & Aquinas, Edward Feser here proves himself a reliable Vergil. Aspects of Aristotelian/Thomistic thought that once seemed to me like no more than antiquated curiosities suddenly come to life as real, philosophically defensible, options. In particular, Feser's defense of the A/T conceptions of efficient & final causation, as against the Humean account that has ruled the roost for the last couple of centuries, is a real eye-opener.
One word of warning: this may be, relatively speaking, a "beginner's guide" to Aquinas, but it is by no means "Aquinas for dummies." Feser frequently addresses recent literature, some of which gets a bit technical. Real "beginners" may need a lot of help from their professors to get the drift.
But, then, that's what professors are for, no?