Author Terry Pratchett died Thursday after a long battle with early onset Alzheimer’s, a disease he called an “embuggerance.†He was 66. Born to a middle-class family outside London, Pratchett worked briefly as a journalist before publishing his first novel, The Carpet People, at age 23. The flat world of that book would later inspire the setting of his crowning literary achievement, the 40-book Discworld series, set in a fantasy world balanced on the back of a giant turtle. Fans were attracted by Pratchett’s trademark blend of light satire and warm humor, and he was the U.K.’s best-selling author of the 1990s. He was knighted in 2009 for his “services to literature,†an honor Pratchett said he was “flabberghasted†by. A year later, he gave a moving lecture about Alzheimer’s, euthanasia, and death for The Guardian, concluding, “If I knew that I could die at any time I wanted, then suddenly every day would be as Âprecious as a million pounds. If I knew that I could die, I would live. My life, my death, my choice.â€