John Peterson 
Aquinas [PDF ebook] 
A New Introduction

Aquinas provides an in-depth analysis of basic philosophical concepts in the thought of Aquinas. These concepts include: being, essence, existence, form, matter, truth, goodness, freedom and necessity, knowledge, willing and choosing, and right action. These ideas are approached from an analytical point of view but the analysis is not exceedingly technical, which allows beginners to follow the discussion. Many other works consider only one aspect of Aquinas’s thought such as his treatment of persons, his arguments for God’s existence, or his theory of truth but Peterson’s Aquinas combines readability with both depth and close analysis to give a comprehensive overview of Aquinas’s work without sacrificing either accuracy or depth.