All these books are free to read: either they're distributed with a free license, or they're in the public domain.
Patricia Elliott and Daryl H. Hepting, editors
Richard Harding and Agustín Guimerá, editors
Google Developer Training team
Ani Adhikari and John DeNero
Andrew W. Neal (editor)
Lara Pauline Karpenko and Shalyn Rae Claggett, editors
Andrea Flynn et al.