I don't know what Harold Bloom was trying to achieve with this book, but his insistence on the highest cultural standards is belied by the whole idea of it. The only people who have any genuine stake in there being such a thing as a Western Canon are tenured professors of literature - obviously, if everybody chucks out Montaigne in favour of Toni Morrison, then Bloom is going to be out of a job. But that ain't going to happen - at least, not outside the frenzied imaginations of elderly professors.
At the risk of making a really terrible pun, a canon appears to be something of which writers are in permanent danger of being violently expelled. I see absolutely no point in trying to affirm some sort of Top Ten, or Top Hundred, or Top 10,000 Great Writers, unless it's to market a fat book on the strength of it. Writing happens, and literature becomes canonical, from the bottom up, not by the fiat of academics. (You may argue that it's academic prestige that in the end gives a book canonical status, but no claret-drinkin', tutorial-givin', pipe-smokin' blow-in is going to persuade me that Saul Bellow is a better writer than Thomas Pynchon, no matter how many more honorary degrees he has. There, I've put my cards on the table.) If anything, this book is a symptom of exactly the kind of superficality Bloom affects to deplore. His narrowness (has this man spent a single week of his adult life off-campus? If so, you'd never tell) is the strongest possible rebuke to his championing of the virtues of reading the classics. He seems to have little to say about these writers other than "Read This!" If books are ultimately only about other books, then there's no point in reading or writing at all.
I gave him two stars on the strength of isolated insights, such as the notion that Emily Dickinson has more "cognitive originality" than any other poet since Dante; an interesting and suggestive idea, pity that Bloom doesn't make more of it.
The endless wittering about Who gets to be in the Canon and Who doesn't and Why ends up making Bloom seem like a cranky pundit during the post-match breakdown on a Saturday sports show. "Well, Borges played a good match, he's a good player, but in the end, Barry, he hasn't the staying power, he hasn't the stamina of a Cervantes, certainly the finest midfielder the Spanish have ever known." You'll get more enlightment browsing in the Classics section of any largish bookshop.
Risible.