The fantasy writer Brandon Sanderson’s reputation is finally as big as his novels — and that’s saying a lot.

His “Words of Radiance” (Tor Fantasy), all 1,087 pages of it, crashed onto the New York Times best-seller list late last month, debuting at No. 1, and has been on it since. The three books he finished in “The Wheel of Time” series after Robert Jordan’s death all hit the top spot, but “Radiance” is Mr. Sanderson’s first No. 1 written by him alone.

“Radiance” is Book 2 in “The Stormlight Archive,” a projected 10-volume series, whose first book, “The Way of Kings,” came out in 2010. “Stormlight” is a sprawling epic set on Roshar, a world regularly scoured by huge hurricanes called highstorms. There are soldiers and scholars, slaves and magic, and Brightlords and Voidbringers. It’s all traditional stuff for fantasy fans, but what sets “Stormlight” apart is how Mr. Sanderson raises genre stakes through detailed world building. The richly imagined books — he calls them a “love letter of sorts to the epic fantasy genre” — also contain notes on Roshar poetry and illustrated tips on how to raise chulls (oversize crustaceans domesticated on Roshar).

As in raising chulls, it takes patience to learn to write fantasy. And for Mr. Sanderson, 38, it hasn’t quite been a straight shot to the top. First, he secured the perfect job in which to hone his craft — working the graveyard shift as a hotel clerk in Provo, Utah. “I was really appreciative of how quiet Provo is after 10 o’clock,” Mr. Sanderson said in a phone interview. After six years, though, all he had to show was a dozen unsold manuscripts. “I was getting stacks and stacks of rejections,” he said in a video interview with the alumni magazine of Brigham Young University, where he went to school. “When you’ve finished 12 novels and haven’t made a single dime, you really ought to take a long, hard look at what you’re doing.”