Yes, you most certainly can. Here's how to do it:

Select the pledge level you want and fund Timeline Fracture.

After you have backed Timeline Fracture, click the "Manage Your Pledge" button.

Add the amount needed to obtain the add-on(s) you want and submit.

Here are the add-ons and their prices:

$5 - a digital copy of Timeline Fracture

$10 - a digital copy of the Kickstarter-exclusive adventure

Do you need any book to play an RPG? No. You could make your game with your own rules. Why do most people not make their own? Because its a ton of work. You have to play test, look for problems, find solutions, and balance the whole experience. Timeline Fracture does the work of balancing and streamlining the use of multiple d20 books and provides a rich, diverse setting so you can just enjoy playing with your friends.

Part of the beauty of the d20 system is that once you learn how to play one d20 game, you know the basic rules for every other d20 game. However, companies that make their own d20 games tweak or change a few things to better suit their games. These changes from game to game become problematic when you mix them together. Most of these problems are fixable, but it takes time and effort to resolve them. When you encounter these problems during a game, it can slow it down to a halt.

Aside from the mechanics, Timeline Fracture offers a coherent world for your game to exist. If you say, "Fantasy", people may think Game of Thrones, Narnia, Lord of the Rings or King Arthur. All of these have fundamental differences in style, tone and setting. The same is true with sci-fi (Star Trek, Mass Effect, Star Wars) and other genres. Timeline Fracture defines each land in the New World, so every player understands what it offers.

Timeline Fracture identifies these differences and problems, offering you solutions before your game even begins.

Yes. Timeline Fracture will not contain the core rules, but if Timeline Fracture is of any interest to you, you probably already own at least one core rule book. Timeline Fracture focuses on streamlining the use of multiple d20 books together and creating the setting for your game not reprinting rules you already have.

In doing my research for this game, I found some very odd games that have d20 stamped on their covers. There are some games that tweak their rules so severely that no don't really resemble the d20 rules that we all know. However, they are the exception rather than the rule. The majority of games keep closer to the established rules and can be used.

For the majority of d20 games, Timeline Fracture provides rules to understand how to convert particular aspects of classes and feats so even those that are a bit different can be used.

By my estimations, no. It will be before that. I made the release date August 2015 to give myself some extra time if something happens. All the computers within five hundred miles of me might spontaneously explode. Something might happen to delay the project from the editor or cover artist. My house might explode. Who knows? I want to make sure that there is enough to deal with such issues without having to tell the backers that Timeline Fracture will be delayed. Best case scenario, there are no delays, and it gets released early.

You're the GM. If you don't like certain books, tell your players they are not usable in your campaign and provide a reason as to why. Just be clear with your players as to why they cannot use those books. Communication is one of the elements in every good game.