Bootstrap changes the way we develop websites in the frontend, and mobile web development has grown incredibly over the past few years. There are over 1.2 billion mobile web users in the world, and 25% of those mobile web users are exclusively mobile. Now, Bootstrap has also gone mobile-first. The mobile-first version of Bootstrap lets you first think about the mobile site and then think about how it expands to larger screens. To build websites for mobile devices that improve the overall experience of your customers, you need to be skilled at using the mobile-first feature of Bootstrap. 'Mobile First Bootstrap' covers the new features in Bootstrap 3 and focuses on how they affect development from a mobile-first perspective.