The mystery is solved: Madonna's brother, Christopher Ciccone, is writing a memoir about his sister, to be released in mid-July by Simon & Schuster with a first printing of 350,000, the publisher told The Associated Press on Wednesday.

The publisher had been promoting a celebrity memoir for July, asking bookstores to order copies without identifying the author or contents.

Persuading stores to make "blind" orders has been tried before. In 2006, William Morrow offered a mysterious tell-all that turned out to be by Princess Diana's former butler, Paul Burrell, who had already written about her. Retailers were angered and the book sold poorly.