Wittgenstein influenced a generation of philosophers and theologians, with works such as Fergus Kerr’s Theology After Wittgenstein showing the relevance of Wittgenstein’s philosophy for contemporary questions in theology. Nature as Guide follows many of the insights of this earlier generation of Wittgenstein influenced scholars, to bring Wittgenstein into conversation with contemporary Catholic moral theology. The first four chapters of the book provides a reading of key themes in Wittgenstein’s philosophy, and draw among others on G.E.M. Anscombe to situate Wittgenstein in relation to the Platonic tradition. Understanding the relationship between grammar, metaphysics and nature is central to this tradition and these themes are examined through an account of Wittgenstein’s philosophical development. These four chapters also provides a critical perspective on Wittgenstein’s thought, engaging with the criticisms of Wittgenstein offered by philosophers such as Rhees Rush and William Charlton. Chapter five lays the groundwork for a dialogue between Wittgenstein and moral theology. Firstly, by examining how open Wittgenstein’s philosophy is to dialogue with theology, and secondly through proposing the use of Servais Pinckaers’ definition of moral theology to structure the conversation developed in subsequent chapters. Pinckaers’ definition is based upon St Thomas Aquinas’ presentation of the principles of human acts in the Prima Secundae of the Summa Theologiae and the final three chapters focus on the question of human acts and their basis in human nature. The reading of Wittgenstein developed in the first part of the book is brought into dialogue with the tradition of Catholic moral theology represented by Pinckaers and other students of St Thomas, such as Anscombe, Josef Pieper, Herbert McCabe, Jean Porter and Alasdair MacIntyre. The book finishes with McCabe’s account of the transformation of human nature through God’s Word, showing how Wittgenstein’s understanding of human practices can shed light on the life of grace.