Roald Dahl was born on September 13, 1916, to a Norwegian family living in Wales. When he was three, his older sister Astri suddenly became ill and died, and his father subsequently lost his will to live, dying from pneumonia shortly afterward. The elder Dahl’s last wish was to put the surviving children in English schools, which he perceived as being superior. As a result, Dahl’s mother could not return to Norway, where she could receive assistance from family.

However academically rigorous English schools might be, the young Dahl found their discipline policies monstrous and oppressive. Decades afterward he would vividly recall his terror at the continual threat of being beaten with a bamboo or wooden cane. This weapon could create vicious welts on its victim’s back and buttocks and leave painful bruises for weeks. Although some of the canings Dahl and his friends received may have been deserved, many of them were the result of the capricious exercise of authority by ill-tempered teachers and older students. The experience left him with a lifelong sympathy for the small and weak and an active detestation of bullies.

However, Dahl’s schooldays were not a period of unremitting horror. While at one school, he was part of a program by which the Cadbury Chocolate Company tested new formulations. At regular periods each student would receive a box containing twenty small bars of chocolate to evaluate. Dahl came to look forward to each distribution, and often imagined the laboratory in which they were created.

When Dahl finished school, he decided not to pursue a university degree because he wanted to see the world. He obtained a job with Shell Oil, which sent him to Tanganyika (now Tanzania) in Africa. While he was there, World War II broke out and he volunteered for the Royal Air Force (RAF). After learning how to fly, he was sent north to another airbase. However, the directions he was given were faulty, and he ran out of fuel before reaching the runway. Injured in the crash landing, he barely escaped his plane before it caught fire.

While he was recuperating from his injuries and it became increasingly clear that he would never again be fit enough to fly, the RAF sent him to Washington, D.C., to serve as an attaché in its embassy. There he was interviewed about his experiences, only to run out of time to answer all of the reporter’s questions. He offered to send the reporter some notes to fill in what he had omitted, but the paper he delivered was practically a finished story. The reporter then suggested that he might have a career in writing.

Dahl proved an adept writer, and after some early realistic stories he began to delve into psychological horror in the tradition of Edgar Allan Poe, albeit in contemporary settings. Even after he returned to England after the war, he continued to find American publications his best markets, simply because they paid so much more than British ones. As a result, he made multiple trips to New York, and on one of them he met his future wife, actress Patricia Neal. He nearly missed the opportunity with her, for while he could be a witty conversationalist, he could also be very rude to those he found boring. The evening he met her, he was more interested in talking with another of his dinner companions, and Neal felt so slighted that when he called to ask her on a date the following night, she turned him down. Only when he persisted did she finally relent.

After they married and had children,...