The Magic Tree House Merlin Missions 4-Book PB Set by Mary Pope Osborne includes the titles “Stallion by Starlight” and “High Time for Heroes.” This fiction book series is targeted towards a young audience aged 9-12 and follows the adventures of characters as they journey through time and explore magical worlds. Published by Random House in the 2000s, these novels are perfect for children who enjoy imaginative and exciting narratives centered around magic and time travel. Each paperback book in the set offers a captivating story that is sure to engage young readers and transport them to new and exciting worlds.