When Robert Jordan - the most popular fantasy writer since Tolkien - died two years ago at age 58, he left behind his "Wheel of Time" saga, unfinished.

Begun in 1990 with "The Eye of the World," the epic tale mixing myth, religion and an ongoing battle to save the world from The Shadow grew to include 11 novels, a prequel and more than 30 million books in print.

This week, "The Gathering Storm" (Tor, $29.99), the 12th book in the series, hits stores. There is a new name on the jacket alongside Jordan's: Brandon Sanderson. The 33-year-old author of "Mistborn" and other fantasy novels was chosen to complete the novel by Jordan's widow, Harriet McDougal, who edited all of her husband's books.

"It was truly (Jordan's) great work and his life's work," says McDougal. Until the week before he died on Sept. 16, 2007, of a rare blood disease called amyloidosis, Jordan was telling his wife "what the series needed to be completed."

McDougal first encountered Sanderson when a friend gave her a copy of a eulogy to Jordan that Sanderson had written. She chose the Provo, Utah, writer in part because "I do think Brandon Sanderson has a natural feeling for the ethical and moral issues of life."

Sanderson has been working with thousands of pages of material Jordan left behind. McDougal has also been involved as the book's editor.

Reading Jordan's unpublished material "was like stepping into Da Vinci's workshop after he just walked off," says Sanderson, who first read Jordan at age 15. Instead of trying to "imitate" Jordan, "I had to adapt my writing to (his) characters."

Says Sanderson: "I know I can't replace him. The person who should have written this book was Robert Jordan. He was the greatest fantasy writer of my generation."

The original plan was to publish one last novel, says McDougal, but the story was so complex, they decided to break the last book into "The Gathering Storm," followed by two more novels, "Towers of Midnight" (out fall 2010) and "A Memory of Light" (fall 2011).

The final chapter, which Jordan wrote before he died, will appear in the last novel.

Jordan's fans are thrilled that the saga is being finished, says Jason Denzel, who runs Dragonmount, the largest Jordan fan Web site. "I can see how someone not familiar with the situation might think, `Oh, they are just doing it for the money.' But they are doing it because it was Robert Jordan's desire and as a token of appreciation for the fans."