The Children of Hurin, by J.R.R. Tolkien, edited by Christopher Tolkien; HarperCollins, 2009, $18.95. Lovers of J.R.R. Tolkien’s Middle-Earth, of The Hobbit and The Lord of the Rings, may return to that realm with The Children of Hurin, published posthumously and with some fairly light-handed editing and explanation by his son. Some who have dipped into The Silmarillion, Tolkien’s uncompleted and posthumously-published account of the Elder Days, have been put off by its high, epic style, without the alleviating homeliness to be found in The Lord of the Rings, or the frequent humour of The Hobbit, as well as by…