I've not been well pleased by this book. Though some of its insights are valuable, and though it is somewhat well researched and fairly comprehensive, it's a chore to read. The author has a style that borders on the incomprehensible -- one feels that he is one of these people who uses tortuous turns of phrase in the mistaken belief that they'll make him seem sophisticated. As a result, the text is disjointed and difficult, its arguments meandering and ill-defined. Williamson has some good ideas, and probably knows what he means, but doesn't get his points across clearly -- it's almost as though he's trying to emulate Eliot's style (or to merely restate the poetry as prose) and, frankly, one often feels as though Williamson has ideas above his station.
In short, this has all of the hallmarks of high school essay-writing -- perhaps the author has spent too long in the company of his students. Using 'difficult' language is neither big nor clever if it serves only to obfuscate meaning; here, the wealth of double-negatives, run-on sentences and unexplained, bewildering conjecture is simply not helpful to the reader of an already difficult poet. If the reader works at it, he or she will gleam some benefit from this book - but there are far better, and better written, works out there. If in doubt, take a look at the excerpts on this site -- it may be that the rather purple prose will appeal to some readers; but I regret that where I had hoped for intelligent discourse, I instead found awkwardly adolescent writing that thought itself more clever than it actually was.