So very earnest. So very full of simple stereotypes. So very well plotted and characterized that I can see why this has remained the most popular beginning chapter book series since I started in the business almost fifteen years ago.
Young siblings Jack and Annie find a mysterious box that they use to travel through time and space, often aided by they box's powerful, magical owner. That's right, in its most basic form the series is Doctor Who for 6-8 year old readers (which has been popular enough to become one of the longest running TV shows of all time). Older Jack (8) is the cautious, studious one who wants to learn before leaping; Annie (7) is the optimistic one who rushes right into everything. It's a perfect combination to establish a balance of adventure and education, with just a touch of tension between them. The tree house's owner provides the mystery.
(This review is for the audio of books 1-8, listened to in immediate succession.)