Explores Aristotle's philosophical method and the merits of his conclusions, and shows how he defends dialectic against the objection that it cannot justify a metaphysical realist's claims. The author does not presuppose previous acquaintance with Aristotle.

I. The emergence of the problem: The problem of first principles; Inquiry and dialectic; Constructive dialectic; Puzzles and substance; The formal cause; Conditions for science; Puzzles about science; II. Solutions to the problem: The universal science; The science of being; Substance and essence; Essence and form; Form and substance; III. Applications of the solution: The soul as substance; Soul and mind; Action; The good of rational agents; The virtues of rational agents; The good of others; The state; Justice; The consequences of virtue and vice; Reconsiderations; Notes

`Undoubtedly a major work - scholarly, learned, detailed ... Irwin's book will certainly be something for Aristotelians to discuss for a long time.' Times Higher Education Supplement `T.H. Irwin's rich book ... is vastly learned ...The argument is always based on a scholarly perusal of the texts; and it is usually presented with philosophical subtelty and precision ... He writes of Aristotle with admiration and with love; and his affection gives a charming blush to a serious book ... already a classic of its kind.' Jonathan Barnes, The Times Literary Supplement 'The book is elegantly printed, and conspicuously well proof-read.' Christopher Kirwan, Exeter College, Oxford, Journal of Hellenic Studies, Volume CX, 1990 'an emminently readable reference book to the history of the field' Pat Haggard, New Scientist, 20 April 1991 `its great strength is that, in spite of its length and scope, Irwin never loses his grip upon a central, organising thesis.' Canadian Philosophical Reviews `This is a very good book. It has much that is original. It is comprehensive ... It is critical ... this is a really important book, and a provocative one; it must be pondered by all who deal seriously with Aristotle.' Ancient Philosophy `remarkable ... This is a scholarly and philosophical work of the first magnitude ... one can only admire the intellectual achievement this book represents, and be grateful for how much there is to learn from it.' Philosophical Review