Yes there is. It is calledQueen of The Nile at Noon.Check on Wikipedia under Mary Pope Osborne. Click on Magic Tree House Series. Scroll down to Magic Tree House Merlin Missions then it is the last one on the list.
Magic Tree House book #39 is called "Dark Day in the Deep Sea".
It is the Magic Tree House 41th book.
Yes, there is a book 46 in the Magic Tree House it's name is Dogs In The Dead Of Night.
Book #41 of the Magic Tree House series is called "Moonlight on the Magic Flute" and is scheduled for release on March 24, 2009.
== == The name of that book is the Eve of the Emperor Penguin.
The very last Magic Tree House book in the series is "Hurricane Heroes in Texas" which is book number 135.
There is no Magic Tree House book with the number 42. The last book in the series is "Balto of the Blue Dawn" which is book 54. The release date for this book was January 5, 2016. You can find it on Amazon.com.
Book number 40 of the Magic Tree House series was published on September 23, 2008. Book number 41 was published on March 10, 2009. Book number 42 was published on Jul 28, 2009. Book number 43 was published on January 12, 2010.
The 20th book in the Magic Tree House series is Dingoes at Dinnertime.
The highest magic tree house book is Book # 55, "Night of the Ninth Dragon."
The 3rd book in the Magic Tree House series is "Magic Tree House #3: Mummies in the Morning".
The 44th Magic Tree House book is A Ghost Tale for Christmas Time and it was published in 2010.