SitePoint gives 75% to 85% discount for all of their e-books in this Christmas holidays. But this offer will close within 21hrs. Hurry up and grab your favorite Book for small amount. Here is the deals page: sale.sitepoint.com. Mostly you will get only the eBooks.
I like their Books because of the illustrated guides. After reading their books, everyone can start the things from the beginning. Explore this products page before buying your books.