"Ranger's Apprentice" is a popular fantasy book series written by John Flanagan. It follows the adventures of a young boy named Will, who becomes an apprentice to a skilled Ranger named Halt. The series is set in the fictional kingdom of Araluen and explores themes of friendship, bravery, and the journey from adolescence to adulthood. Throughout the series, Will learns the ways of the Rangers, including archery, stealth, and survival skills. He faces various challenges, including battles against enemies like the Temujai and the Morgarath. The story emphasizes the importance of loyalty and courage as Will and his friends embark on quests to protect their kingdom.