Offline
All I've read on freedom of the will from a classical perspective is Agustine's treatise. Wednesday I'm having a discussion with a materialist who nevertheless holds libertarian views on the will ("the brain acts freely" IIRC). I'd love any material worth reading, since this is not an area of normal concern for me.
Offline
I don't know any books that talk about freedom of the will from a Classical perspective. However, I do know about J.R. Lucas' book "Freedom of the Will," and I believe it talks about related matters.
Offline
I'm not sure whether there is anywhere it is treated especially in depth. Aquinas mainly observes that only the universal good is willed of necessity, whereas any limited good is not. Further, since the will is man's rational appetite, he says that it cannot be efficiently caused by any body.