While most of the reviews so far have complained at the lack of information in this book, that's not the issue that brings my review down to a rather sad and lonely single star.
Indeed, while you have to read the detailed product information to find out that it's only an Atlas, the info is there, so it's hard to blame Prima too much on that front.
Unfortunately, the Atlas itself is the problem. To start, the book is not physically large, limiting the quality and usefulness of any maps included. What do you expect from a good atlas? Large, clear images, with plenty of room for detailed notation. This book has neither the large images or the detailed notation. The maps inside are the same monochrome blue maps from in game, and indeed, judging by the blurriness of "larger" images, appear to simply enlarged screenshots, at that.
Each map includes -very basic- notation; Speeder routes, quest givers, trainers, and vendors. Things that are not included (or, are included so rarely and randomly as to be comical) include the locations of Vaults, Respec "trainers", crafting trainers, Lore objects, guaranteed loot chests, etc. These are -sometimes- included as "Objects of special interest." Far more often than not, they are not included at all. In short, the atlas manages to actually reveal -less- than your in-game map does, and in smaller, harder to read images.
The atlas also inexplicably omits entire zones. The maps for Alderaan, for example, include only the primary overview map of the planet (a massive landmass zoomed out so far as to be pointless, used only to demarcate the individual zones), the detail map of the first zone, and the detail map of select interior locations. The detail maps of the subsequent Alderaan zones? Nope. Not there. On the other hand, the maps for Balmorra are repeated, twice each. Quite a few planets lack full detailed maps of every zone, which, for a dedicated Atlas, is inexcusable.
There are only two reasons I can see to purchase this book. First, it -does- list the location of every Datacron, in a general way. It won't tell you precisely how to get to them, but it will mark the area of the map where you should be looking. If you just can't wait for this info to inevitably turn up online, and with more detail, this book will help. Second, if you are simply a huge Star Wars or Old Republic fan, it's a fairly good looking piece to sit with the rest of your collection, for the low price. Just as long as you only open it for the small concept art section at the back of the book.