this looks good and i think it'll work pretty well. but, i'd like to draw your attention on a few things. First, purchase buttons seem to be quite colourless. they're not attracting.maybe making the corner sharp rather than round and/or using vibrant colours could solve the problem. the green colour of the price is really boring. second thing is that the alignment of items under Things You Will Learn could be left instead of center. As it is now, it looks un-professional. Last of all, it might be a good idea to present some brief information about the authors somewhere at the bottom or in sub-pages.
I think you have a good design here but it could benefit from some detail work to make it more exciting. Whenever you use a dark strong with a drop shadow like you are here, it seems to blend together and makes the stroke look like it's feathered. I would maybe use an off white stroke. Think about putting a subtle texture in the background as well to liven things up. Overall this looks good, stay the coarse, just modify a few things.