In Phoenix the parallels with totalitarian regimes are made more explicit. Tolkien always strenuously denied that The Lord of the Rings was an allegory of Nazi Germany; Rowling, whose books are essentially a Tolkien-by-numbers for younger readers, makes a virtue of such comparisons: "They thought Voldemort had the right idea," says Sirius of his dead parents, "they were all for the purification of the wizarding race, getting rid of Muggle-borns and having pure-bloods in charge. There were quite a few people, before Voldemort showed his true colors, who thought he had the right idea about things."
She's not preaching, but there are weightier things in these last two books than simply the rules of Quidditch and the transfiguration of toads, just as Harry, at 15, is made to understand that there are graver things in life than detentions and his ongoing feud with Professor Snape.
Finally, to the crucial plot points that have generated so much online speculation and feverish activity at the bookies. Hogwarts does acquire yet another new Defense Against the Dark Arts teacher -- a position unenviably akin to being drummer in Spinal Tap -- but it's none of the obvious contenders.
There is a fantastic battle and - as Rowling included in the brief notes she allowed to be auctioned last year - there is a death of a major character, but again, it foils expectation (except, possibly, the expectation of the bloke who bet pounds sterling 20,000 on a certain character a couple of days after the Merseyside lorry heist).
We learn Voldemort's real name, which is bizarrely anticlimactic, rather like learning that Satan's first name is Derek, and we learn, most importantly, the true prophecy that links Harry and Voldemort.
It's a beast of a book, but there's no question of Rowling losing the plot.