Renaissance and Enlightenment philosophers arbitrarily restricted reason, with disastrous consequences for human understanding. This book explains why the restoration of reason to its full breadth and power is in order. Montague Brown discusses how and why modern thought focused its efforts too narrowly on one portion of the spectrum of realities with which human reason ought to concern itself (truth) and so became incapable of handling moral (goodness) and aesthetic (beauty) topics adequately. The new focus produced unprecedented achievements in science and technology, but in other areas it produced significant losses. Brown explains how pre-Enlightenment thought avoided such narrowing and how post-Enlightenment philosophers have tried to redress it. Finally, he presents his own classically grounded proposal. Philosophy and theology students and thoughtful lay readers will appreciate this book.