Question: How many books are in the Stephen King series of which Roland Deschain of Gilead is the protagonist?
Sentence (from "The Dark Tower V: Wolves of the Calla"): Prior to the novel's publication, two excerpts were published: "Calla Bryn Sturgis" was published in 2001 on Stephen King's official site, and "The Tale of Gray Dick" was published in 2003 in "McSweeney's Mammoth Treasury of Thrilling Tales".
Relevant evidence: No