THE FOUNDATIONS OF MO RALITY. Henry Hazlitt. D. Van Nostrand Co., Inc., Princeton, N.J. 398 pp. $9.95. J N the preface to this most inter· esting and highly instructive volume, the author states that in writing it he sought "to present a unified theory of law, morals, and manners." In this attempt within a field that for several millenia has occupied the minds of thinkers he has touched upon problems the so· lutions to which were never of greater urgency than they...