Seeking what he describes as "the utmost limit of the knowledge our natural reason can achieve . concerning the True Existence [that is God]," John Duns Scotus (1265-1308) offers in this treatise one of philosophy's most rigorous and ambitious attempts to deduce God's existence from purely metaphysical theorems. As elucidated by its concise philosophical commentary, Thomas M. Ward's new translation of the Treatise on the First Principle puts a masterpiece of natural theology within reach of a new generation of English-reading students of philosophy.