This interdisciplinary commentary makes Thomas Aquinas's classical treatise on the meaning of life and the nature of human happiness luminously clear to scholars, students, and general readers. Budziszewski offers a line-by-line explanation of the text, complete with examples, applications to life, and ancillary discussions. 'Professor Budziszewski is among the rare scholars who combine depth and erudition with a real flair for writing. No matter how dry or formidable one imagines Thomas Aquinas to be, his words come alive through the pen of Budziszewski. One sees with new eyes how amazingly pertinent Aquinas's questions are, how intriguing the puzzles with which he wrestles, and how sensible the answers at which he arrives regarding the meaning of life. This book will be a godsend for classroom study.' Matthew Levering, James N. and Mary D. Perry Jr, Chair of Theology, Mundelein Seminary