A modest helping of philosophical broth, clean but thin, instead of the hearty stew it might have been. The sextet--truth, goodness, beauty (""ideas we judge by""), justice, equality, and liberty (""ideas we act on"")--could obviously get no more than summary treatment in a single volume. Even so, readers who happen not to share Adler's commitment to realism in general and Aristotle in particular are going to come away hungry--and unconvinced. Early on, Adler declares that truth consists in the correspondence between mind and reality, and before long he's talking about ""objective truth,"" which is ""forever and immutably true."" Augustine and Aquinas, among others, would agree, but what about, say, William James and his friends the radical empiricists? Though Adler nods amiably in the direction of pragmatism in his next-to-last chapter, he never seriously considers the pragmatist's assumption that there is no one Truth, only an infinite series of truths, all of them conditional handholds on a constantly changing reality. On the ethical side of the fence (the student may well question this and other traditional divisions, e.g., between knowledge and taste), Adler is a little more flexible. He broadens his basic natural-law position by allowing the utilitarians to get in a word or two. But here also he's one-sided and relentlessly abstract: he gives no hint, for instance, as to how one might implement one of his principles of justice, ""To each the wealth that he produces."" Still, his exposition is lucid and sensible--if the reader doesn't mind Adler's somewhat narrow advocacy of the ""perennial philosophy.