Which short story collection did J.K. Rowling publish in 2008 for charity?

J.K. Rowling published The Tales of Beedle the Bard in 2008 for charity.

The collection contains five wizarding fairy tales mentioned in Harry Potter and the Deathly Hallows. The best known is “The Tale of the Three Brothers,” which explains the origin of the Deathly Hallows. Each story is followed by commentary attributed to Albus Dumbledore.

Rowling donated the proceeds from the original editions to the Children’s High Level Group, the organisation that later became Lumos. The book therefore works both as a companion to the Harry Potter series and as a fundraising publication. It was released in December 2008.