Harry Potter and the Half-Blood Prince by J.K. Rowling — book slip

In "Harry Potter and the Half-Blood Prince," the wizarding world is in turmoil as the war against Voldemort intensifies. Harry Potter returns to Hogwarts for his sixth year, where he discovers a mysterious book belonging to the enigmatic Half-Blood Prince, which aids him in his Potions class. Under Dumbledore's guidance, Harry delves into Voldemort's past to uncover the secrets that might lead to his downfall. Meanwhile, teenage life continues with its usual mix of romance, rivalry, and the challenges of growing up. As danger looms ever closer, Harry and his friends must prepare for the battles ahead.

Sixth book in the Harry Potter series.