Christopher Hitchens on J. K. Rowling—
“We must not let in daylight upon magic,” as Walter Bagehot remarked in another connection, and the wish to have everything clarified is eventually self-defeating in its own terms. In her correct determination to bring down the curtain decisively, Rowling has gone further than she should, and given us not so much a happy ending as an ending which suggests that evil has actually been defeated (you should forgive the expression) for good.
Greater authors— Arthur Conan Doyle most notably— have been in the same dilemma when seeking closure. And, like Conan Doyle, Rowling has won imperishable renown for giving us an identifiable hero and a fine caricature of a villain, and for making a fictional bit of King’s Cross station as luminous as a certain address on nearby Baker Street. It is given to few authors to create a world apart, and to populate it as well as illustrate it in the mind.
"A fictional bit of King's Cross Station"—
Throughout the series, Harry has traveled to King's Cross Station, either to depart for Hogwarts or return to London on the Hogwarts Express. The station has always symbolized the crossroad between the Muggle world and the Wizarding realm and Harry's constant shuffling between, and his conflict with, the two extremes. As Harry now finds himself at a transition point between life and death, it is purely to be expected that he would see it within his own mind as a simulacrum of that station. And though Dumbledore assures Harry that he (Harry) is not actually dead, it seems Harry can choose that option if he so wishes. Harry has literally and figuratively been stripped bare, and must decide either to board a train that will transport him to the "other side", or return to the living world…. — Wikibooks.org