Time doesn't really exist, it's all math and logic, and in theory, you could determine everything that is ever going to happen if you had enough information. Time travel, is possible in the form of pure information (predicting exactly what will happen in the future), and therefore, you could in theory...with enough information.....determine a book that was going to be created in the future, and instead create it now. It should be mentioned that even that act, and the creation of the book at an earlier time, could also be predicted by someone who had enough information....and yet again, that person could then create the book even earlier.
There is nothing random in the universe, everything is happening in a logical order...so time travel, or predicting the future (or determining exact past events) is totally possible. Physically traveling through time requires the ability to change the universe to a previous template, or a future template based on predictions, and would require a massive computer.