Only the laughably gullible could be fooled by this mish-mash of twaddle. More apt title would have been Lectures in Ancient Twaddle. Just because it says its philosophical doesn't mean that it is. It has an amusement factor though, especially if read with Foucault's Pendelum, by Umberto Ecco.
As is often the case with Manly Hall, this book is deceptively clear. Much of what he says sounds obvious and easy to understand -- until you put the book down and try to understand the authors he's written about. Then you will find that he has brought a wonderful clarity to the essential truths of ancient philosophy, delivering the heart of wisdom without the encumbrances of academic verbiage. An excellent starting-point for young people interested in the great visionaries of the past, and an enlivening refresher for those bogged down in the tedium of classical philosophic texts.