A reference work, it features a number of writers who provides scholarly essays on the thoughts of the Italian Catholic philosopher and theologian Thomas Aquinas, collectively known as Thomism.

A reference work to the Italian Catholic philosopher and theologian Thomas Aquinas, the book contains ten chapters and begins with an editorial introduction by Norman Kretzmann and Eleonore Stump.

In a review to The Journal of Religion, Joseph Wawrykow of the University of Notre Dame commended the editors for recruiting experts in the field of medieval philosophy, especially Thomism, to write the essays in the book.

"[1] Williell R. Thomson of Speculum began his review by comparing it to other books of the Cambridge Companion series and added "the present volume anatomises its subject into ten more or less self-contained subsystems and devotes a chapter by an acknowledged authority to each".

[2] Thomson, however, questioned the reasons behind the authors who are all from North American institutions (except Jan A. Aertsen of the Vrije Universiteit Amsterdam, who wrote the first chapter) and wondered if there have been a few European Thomists; he suggested that the answer should have been written in the introduction.

[3] He concluded his review by writing that the book, not only a valuable guide to the school of thought, can help "the perceptive and diligent reader to some of the unresolved issues in a vibrant and engaging field of scholarship".

[8] Timothy McDermott of the New Blackfriars bemoaned that the companion focuses more on Aquinas only as a philosopher than theologian, and saw the final chapter, written by Stump, as not substantially contributing to the book.

[9] A reviewer in the Zeitschrift für philosophische Forschung commended The Cambridge Companion to Aquinas's essays, saying they are informative and clearly written while also free from apologetic tones.