That’s a phenomenal number, but just start almost any of Dahl’s books, then try to stop reading. I can testify to the tractor-beam power of his storytelling. After finishing Dennison’s biography, I decided to glance briefly at the opening chapters of “The Witches,” which I had reviewed, ecstatically, when it first appeared in 1983. When I finally lifted my eyes from the page, I was a quarter of the way through the novel, having been caught up all over again in its delicious scariness. Admittedly, “The Witches” remains my favorite among Dahl’s classics, closely followed by his 1988 paean to books and girl power, the wonderful “Matilda.” I didn’t reread it only because I had watched the exuberant — if overly dark — new film version instead. Like nearly all of Dahl’s best work, these two novels celebrate kindness, independent thought, daring, loyalty and self-reliance.

Without supplanting either Jeremy Treglown’s pioneering “Roald Dahl: A Biography” (1993) or Donald Sturrock’s authorized biography, “Storyteller” (2010) — both of which I recommend, especially the latter — this succinct new biography provides just enough information for all but the most ardent Dahl devotee. As in his previous lives of Beatrix Potter and Kenneth Grahame, Dennison again reminds us that children’s authors are, to say the least, complicated people. Dahl, for instance, could face horrific life-or-death crises with heroic self-control, knowing precisely what needed to be done and doing it. In more ordinary circumstances, however, his need to dominate and take command wasn’t much different from that of his own villain, the controlling, paramilitary sadist Miss Trunchbull.

Yet Dahl remains a troubling, complicated figure. Waspishly opinionated, frequently offensive, a hard bargainer with publishers and swaggeringly obnoxious with his editors, he could also be irresistibly charming, outrageously funny and, in his younger days, a relentless Casanova [ . . . ]