#1 they are using tracking from the program they used to create the book.
#2 they animated it in a 3d program most likely
#3 yes they used a 3D program to create the book and the desk
#4 in the 3D program they animated the camera to do this to make it more interesting and show off the 3D and tracking abilities.
learn how to do it probably in Maya then the only thing in ae that was done was probably just the images in the books and their animations.
The footage of the book could have been created with just about any 3D software. Adding the images was just a layer with an animated mask that was brought in and taken out after the pages flipped. Easily done in AE. There was a bit of camera motion on the book that was tracked. There are a bunch of ways to do this in AE. Personally I'd stabilize for scale and rotation then add my images, then remove the stabilization from the shot and add it to the images. Here's the technique for that:
The really good way to do something like this would be to set up your pages as layers with the photos already on the pages, pre-compose the page and photo, build up a book in AE with a bunch of pre-comps set as 3D layers, offset in Z by about 2 pixels and set the anchor point to the binding edge, then rotate the pages and either use Mesh Warp or AE's 3D-Rendering engine and bend the pages. Now you've created the entire thing in AE.
The other, even better option, would be to create the book in a 3D app. Blender (blender.org) is a free app that is more than capable of producing this kind of animation, and use texture mapping to put the photos on the pages, then render out several different passes, diffusion, ambient occlusion, shadow, and so forth, then composite and correct for color in AE.