Magic Tree House, Books 50 & 51

Hurry Up, Houdini!
Jack and Annie are heading out on another mission for Merlin the magician! This time they have to find a famous stage magician, the great Harry Houdini. But when the magic tree house whisks them to Coney Island, they land in an amusement park. They will have plenty of time for fun before Houdini performs—and plenty of time to get into trouble!
This time the trouble is between Jack and Annie. When they have an argument, it looks as if they won't complete their mission for the first time ever. Will they get along in time for Houdini's magic show? What will they have to do to meet Houdini? The answers come with laughs and a surprise ending!
Mary Pope Osborne fills Hurry Up, Houdini! with her trademark combination of history, mystery, and fantasy . . . and a bit of showbiz as well!
High Time for Heroes
Jack and Annie must find another secret of greatness for Merlin the magician! This time, their mission takes the time-traveling pair to the Nile River in Egypt in the mid-1800s. They're looking for an unusual hero in history, the world's greatest nurse—Florence Nightingale!
But when Jack and Annie find the famous woman, they discover that she's unhappy with her life and can't help them. Can they help her instead? And could a baby baboon, a bad accident, and a few daring acts of heroism help them all?
Mary Pope Osborne blends chills, thrills, and spills in another amazing addition to the bestselling Magic Tree House series.