"Order of the Phoenix" is the fifth book in the Harry Potter series by J.K. Rowling. It follows Harry Potter as he returns to Hogwarts School of Witchcraft and Wizardry for his fifth year, facing challenges from both the school administration and the dark forces of Lord Voldemort. The story introduces the Order of the Phoenix, a secret group formed to fight against Voldemort and his followers, the Death Eaters. As Harry struggles with the pressures of adolescence and the return of dark magic, he learns the importance of friendship, loyalty, and standing up for what is right.