Aquinas

is an excellent book edited by Anthony Kenny (isbn 0-19-287500-0). As usual I'm going to quote from a few pages:
We employ the word 'think' in two quite different ways; we talk of thinking about something, and we talk of thinking that something.
Intellectual activity, then, is regarded as in some way dependent on sense-experience; in some sense of the word Aquinas is an empiricist. Many empiricist philosophers have held that all our ideas arise from sense-experience, and that they are required by abstraction from or selective inattention to features of that experience.
When I look at myself in the mirror, I 'see' myself rather than seeing the mirror, unless I am making an especial effort to attend to the mirror.
A man cannot know what a whole is or what a part is except through the possession of concepts or ideas derived from experience.
A sense faculty which cannot go wrong is not a sense-faculty at all.
The oldest Oxford and Cambridge colleges were still in the future; just after Thomas was lecturing on the Sentences in Paris the delinquent baron, John de Balliol was ordered, as a penance, to found a house of scholars in Oxford.
As Wittgenstein once observed, it is not the answers which Aquinas gives, but the questions which he asks, which are the measure of his philosophical gifts.