Usually any art book contains concept art and character & enemy designs, but probably due to Naughty Dog's nature (the company responsible for the videogame), in The Art of Last Of Us there is an incredible amount of beautiful scenery, iterations of not only the main characters but also non-player characters and monsters, examples of different lighting tests on scenes...
I loved the videogame, and the book doesn't disappoints, showing sketches, different steps and iterations (including discarded ones), colouring... Special mention to the faces: You clearly feel how much effort was put on trying to find "the perfect match" for each character face, different expression tests, or details like hair color. And the same applies to enemies: Lots of iterations on the type, clothing and weaponry.
A nice collector's item indeed.