Pope Osborne, Mary "Magic Tree House" Series

Pope Osborne, Mary "Magic Tree House" Series - 1992 ff.

Jack and Anne are two ordinary children who just have to enter their tree house and, with the help of magical books, can travel back in time. In the various books they learn everything about history but also a lot about science. A very interesting way of teaching children all sorts of important subjects.

My sons really enjoyed these books.

These are all the books that exist (UK titles in brackets, when different).
[Research Guides in brackets]

Book 1: Dinosaurs Before Dark (Valley of the Dinosaurs) [RG1: Dinosaurs]
Book 2: The Knight at Dawn (Castle of Mystery) [RG2: Knights and Castles]
Book 3: Mummies in the Morning (Secret of the Pyramid) [RG3: Mummies and Pyramids]
Book 4: Pirates Past Noon (Pirates' Treasure) [RG4: Pirates]
Book 5: Night of the Ninjas
Book 6: Afternoon on the Amazon (Adventure on the Amazon) [RG5: Rain Forests]
Book 7: Sunset of the Sabertooth (Mammoth to the Rescue) [RG12: Sabertooths and the Ice Age]
Book 8: Midnight on the Moon (Moon Mission) [RG6: Space]
Book 9: Dolphins at Daybreak (Diving with Dolphins) [RG9: Dolphins and Sharks]
Book 10: Ghost Town at Sundown (A Wild West Ride)
Book 11: Lions at Lunchtime (Lions on the Loose)
Book 12: Polar Bears Past Bedtime Icy Escape) [RG 16: Polar Bears and the Arctic]
Book 13: Vacation Under the Volcano (Racing with Gladiators) [RG14: Ancient Rome and Pompeii]
Book 14: Day of the Dragon King (Palace of the Dragon King)
Book 15: Viking Ships at Sunrise (Voyage of the Vikings)
Book 16: Hour of the Olympics (Olympic Challenge!) [RG10: Ancient Greece and the Olympics]
Book 17: Tonight on the Titanic [RG7: Titanic]
Book 18: Buffalo Before Breakfast
Book 19: Tigers at Twilight
Book 20: Dingoes at Dinnertime
Book 21: Civil War on Sunday
Book 22: Revolutionary War on Wednesday [RG11: American Revolution]
Book 23: Twister on Tuesday [RG8: Twisters and Other Terrible Storms]
Book 24: Earthquake In the Early Morning
Book 25: Stage Fright on a Summer Night
Book 26: Good Morning, Gorillas
Book 27: Thanksgiving on Thursday [RG13: Pilgrims]
Book 28: High Tide in Hawaii [RG15: Tsunamis and Other Natural Disasters]
Book 29: Christmas in Camelot
Book 30: Haunted Castle on Hallows Eve
Book 31: Summer of the Sea Serpent
Book 32: Winter of the Ice Wizard
Book 33: Carnival at Candlelight
Book 34: Season of the Sandstorms

Book 35: Night of the New Magicians
Book 36: Blizzard of the Blue Moon
Book 37: Dragon of the Red Dawn
Book 38: Monday with a Mad Genius [RG19: Leonardo da Vinci]
Book 39: Dark Day in the Deep Sea [RG17: Sea Monsters]
Book 40: Eve of the Emperor Penguin [RG18: Penguins and Antarctica]
Book 41: Moonlight on the Magic Flute
Book 42: A Good Night for Ghosts [RG20: Ghosts]
Book 43: Leprechaun in Late Winter [RG21: Leprechauns and Irish Folklore]
Book 44: A Ghost Tale for Christmas Time [RG22: Rags and Riches: Kids in the Time of Charles Dickens]
Book 45: A Crazy Day with Cobras [RG23: Snakes and Other Reptiles]
Book 46: Dogs in the Dead of Night [RG24: Dog Heroes]
Book 47: Abe Lincoln at Last! [RG25: Abraham Lincoln]
Book 48: A Perfect Time for Pandas [RG26: Pandas and Other Endangered Species]
Book 49: Stallion by Starlight [RG27: Horse Heroes]
Book 50: Hurry Up, Houdini! [RG 28: Magic Tricks from the Tree House #28]