NEW YORK (AP) — The saga of how cult sci-fi novel “Dune” slowly permeated the mainstream over decades is a tale with almost as many twists and turns as “Dune” itself, and author Ryan Britt recounts it in the lively and entertaining “The Spice Must Flow.” As Britt details, author Frank Herbert began to plot the novel — about a young boy named Paul Atreides who may be the future leader of the galaxy — after doing research for a nonfiction article about a manmade technique to stabilize sand dunes. Much of the action takes place on Arrakis, a desert planet that has reserves of a precious natural resource, spice, and is infested with sandworms, Herbert’s iconic dune creature. Herbert had authored sci-fi short stories and novels before, but the only place he could find willing to publish “Dune” in 1964 was an auto-repair book publisher.