The Harry Potter prequel is an 800-word story written by J. K. Rowling, and was published online on 11 June 2008. Set about three years before the birth of Harry Potter, the story recounts an adventure experienced by Sirius Black and James Potter.

At the bottom of the card, JKR wrote: "From the prequel I am NOT working on - but that was fun!"

There is no official 'cover' for this short story, seeing as it was penned (By JKR) on an A5 card for the auction by bookseller Waterstone's, in aid of two reading charities, Dyslexia Action and English Pen. It was auctioned off for £25,000.