Roald Dahl wrote in a small wooden hut at the bottom of his garden in Buckinghamshire, England. The hut had a wing-back armchair, a wooden writing board across his knees, and yellow lined paper. He wrote every morning with the same kind of pencil, and he sharpened them six at a time.
Dahl loved inventing words. The BFG (the Big Friendly Giant) speaks in his own special language. Snozzcumbers are vegetables. Frobscottle is a fizzy drink that makes whizzpoppers. Scientists who study language call invented words like these 'Gobblefunk' - which is itself a Dahl word.
He often put a little bit of himself into his books. In Boy: Tales of Childhood, he wrote about growing up at school, the sweet shops he loved, and once being asked to taste-test chocolate bars for Cadbury - which gave him the idea for Charlie and the Chocolate Factory years later.
His writing hut is still there today, looked after by his family. You can visit it (carefully kept exactly as he left it) at the Roald Dahl Museum in Great Missenden. The pencil shavings on the floor are real.