* Mister Rogers, who has smoothed many a child's anxieties over going to day care, meeting the doctor, welcoming a new baby, moving to a new house and making friends with the potty, now adds "When a Pet Dies" and "Going to the Hospital" (both Putnam, $12.95) to his series of "First Experience" books.

* In hardcover sales last year, Stephen King occupied three of the top 10 spots, led by "The Tommyknockers" with sales of 1.4 million copies. In paperback last year, four King books each had more than two million copies in print.So how many copies can King sell in audio? That question is going to be tested with the "The Dark Tower: The Gunslinger" (New American Library, $29.95, six hours and 16 minutes). It is not King's first appearance on audio, but this is the first reading by King and the first to receive the kind of priority treatment normally reserved for potential print blockbusters.

* Author William Cox, who specialized in paperback sagas dramatizing life in the Old West, died at his typewriter while writing his 81st novel, his widow said. He was 87.

In addition to his 80 novels, Cox wrote about 1,000 short stories, 100 television scripts and screenplays. His efforts ranged from newspaper sports stories to popular pulp tales for "dime magazines" in the 1920s and 1930s. Later, he focused on writing Westerns, including "The Six Horsemen," "Chicano Cruz," and the "Cemetery Jones" series.