J. K. Rowling had more magic up her sleeve after all.

Over the weekend the Sunday Times (London) disclosed that she is the author of 'The Cuckoo's Calling,' a well-reviewed crime novel issued in April under the pseudonym Robert Galbraith.

The book, which features a private investigator named Cormoran Strike, who lost a leg in Afghanistan, quickly zoomed up the charts Sunday after Ms. Rowling was identified as the writer. The author had originally been described as having served in the military, where his experiences helped shape the novel.

The book was published in the U.S. by Mulholland Books, an imprint of Lagardère SCA's Hachette Book Group, and by a sister imprint in the U.K.

By early Sunday afternoon, the physicaledition ranked No. 1 at Barnes & Noble Inc.'s online store and at Amazon.com Inc. in the U.S. A Barnes & Noble spokeswoman described the title as a slow seller until Ms. Rowling was identified as the author.

By late Sunday afternoon, 'The Cuckoo's Calling' was temporarily out of stock online at BarnesandNoble.com, while Amazon said that the title 'usually ships within 10 to 14 days.' A spokeswoman for Barnes & Noble noted there is still 'some availability' in stores.'

Mulholland will publish a second book in the series next summer, said Reagan Arthur, publisher of Hachette's Little, Brown & Co., in a prepared statement. She also said that 'The Cuckoo's Calling' is being reprinted and that the edition will state that Robert Galbraith is a pseudonym for J.K. Rowling.

An independent retailer in the Midwest said she understood Ms. Rowling's desire for a clean slate. 'I think she did this so that she could write freely without expectations from her audience,' said Sarah Bagby, owner of Watermark Books & Café in Wichita, Kan., which stocked the book when it came out in April.

A spokeswoman for Ms. Rowling confirmed the author's identity via an email but declined further comment.

Ms. Rowling is best known for her wildly popular seven Harry Potter novels, all of which were made into films. Although her first adult novel, 'The Casual Vacancy,' received mixed reviews last fall, it proved popular with readers.

On Sunday, Michael Pietsch, chief executive of the Hachette Book Group, said 'The Casual Vacancy' has sold more than a million hardcover copies in North America since publication and was the group's biggest selling hardcover title in 2012.

Earlier this year, a 'rich list' published by the Sunday Times, which like The Wall Street Journal is owned by News Corp, estimated Ms. Rowling's fortune at £560 million ($846 million).

The Harry Potter series has sold more than 450 million physical copies world-wide, according to Scholastic Corp., which publishes the books in the U.S. Scholastic is in the process of issuing new fancy paperbacks with new cover illustrations.