He helped invent a medical valve
In 1960 Dahl's baby son Theo was hit by a taxi in New York and developed hydrocephalus, a build-up of fluid on the brain. The shunts used to drain it kept clogging, and each blockage meant emergency surgery.
Dahl went to a toymaker he knew — Stanley Wade, who built precision hydraulic pumps for model aeroplane engines — and to Theo's neurosurgeon Kenneth Till, and the three of them designed a valve that did not jam. The Wade-Dahl-Till valve was used on around three thousand children worldwide. Theo recovered enough not to need it himself. Dahl took no money from it.
The hut at the bottom of the garden
He wrote in a brick shed he never let anyone clean, sitting in an old armchair with a sleeping bag over his legs, a board across the arms and a thermos. Six yellow pencils were sharpened before he began. He worked two hours in the morning and two in the afternoon, and he wrote on yellow American legal paper shipped over specially, because he had decided years earlier that it was the right paper.
The room also held a ball of silver chocolate wrappers he had been adding to since the 1930s and a piece of his own hip bone. He was a fighter pilot before he was a writer, crash-landed in the Libyan desert in 1940 and fractured his skull, and always said the writing began with an article about that crash.
Children can take much more than adults expect
Dahl's deliberate position was that children like their villains thoroughly horrible and their justice absolute. Miss TRUNCHBULL swings a girl by her pigtails. The TWITS put glue on a branch to catch birds for a pie. The WITCHES want to turn every child in England into a mouse, and one boy stays a mouse at the end of the book.
Adults complained constantly, which he regarded as evidence it was working. His actual rule was narrower than it looks: the nastiness is always aimed at cruel grown-ups and never at the child reading, who is reliably smarter than the adults in the story. MATILDA beats the headmistress with her mind. CHARLIE wins because he is the only honest one in the FACTORY.
The books, and a recent argument about them
The grid holds most of the shelf: JAMES and the giant PEACH, CHARLIE and Willy WONKA's chocolate FACTORY with the OOMPA-Loompas and the greedy Augustus GLOOP, MATILDA and Miss HONEY, DANNY the champion of the world, FANTASTIC Mr Fox, the BFG among the GIANT-s, the enormous CROCODILE, the GIRAFFE and the Pelly and me, and ESIOTROT, which is tortoise backwards.
In 2023 his publisher issued editions with hundreds of small changes — words about weight, appearance and gender altered or removed. The reaction was loud enough that within days they announced the original texts would stay in print as well, so both versions now exist. It is a live argument about what you do with an old book that children still read every day, and there is no tidy answer to it.