New York ? Having already conquered the children’s market, Scholastic Inc., the U.S. publisher of J.K. Rowling’s multimillion-selling “Harry Potter” series, is targeting adults, ages 18 to 35. Potter ads featuring bikers, skateboarders and couch potatoes will appear in Rolling Stone and other magazines throughout October.

“We felt we needed to think out of the box and reach out to readers who would not normally pick up a copy of Harry Potter unless somebody placed it in their hands,” Barbara Marcus, president of Scholastic Children’s Books, said this week.

Besides Rolling Stone, the promotions also will run in US Weekly, Outside Magazine and Time Out New York, the only one of the four magazines in which Scholastic has advertised before.

Statistics released Tuesday by Scholastic makes you wonder how many readers are left to reach. Sales for “Harry Potter and the Order of the Phoenix,” the fifth of a planned seven Potter books by Rowling, have reached 11 million just three months after publication. That exceeds the announced print run of 9.3 million.

Grown-ups have long been an important market for the Potter books, with a consumer study released in 2000 showing that 43 percent of purchases were made by adults.

“But there’s a strong 18-35 demographic that may not have come into contact with Harry, people who probably don’t have children,” Marcus said.