Everyone must become a philosopher. The alternate is to forego living a human life, or as D. Q. McInerny illustrates, to run while choosing to be hamstrung. But not all philosophizing is equal, and it requires discipline and systematic study. In "creative impatience with ignorance" and "an unswerving commitment to the truth," one can be confident he is at least moving in the right direction toward genuine philosophy. But most importantly, philosophy requires teachers. To philosophize is, after all, to be an eternal student, a person who even while instructing others relies on the guidance found in the 'fertile' human wisdom cultivated throughout the ages. And the most fecund of all philosophy, according to McInerny, is that contained in Aristotelian-Thomism. His concise and thorough defense of the philosophical life and its lodestar, Thomism, must be read as deliberately as it was written. For McInerny makes a bold claim: if one is truly serious about philosophizing, an encounter with the essentials of Thomism is fundamental and indicates a path for the human mind unlike anything other systems or traditions of thought can offer.  This book begins with logic and is followed by introductions to the philosophy of nature, philosophical psychology, epistemology, ethics, political philosophy, metaphysics and natural theology. It is a companion for students of all ages who have yet to spend quality time with Thomas Aquinas. And it is a real delight to do so in the company of McInerny, who in Being Ethical (2019) has already proven himself to be the affable and able teacher every thinking person longs to meet along the course of his search for truth.