Dreamweaver CS5.5 includes new tools to help web designers build sites that adapt to different screen sizes and devices. This includes support for HTML5, CSS3, and frameworks like jQuery Mobile. The book guides readers through case studies that redesign a site to work on desktops, tablets and phones using these technologies. It also covers building mobile apps using PhoneGap. Overall, the book aims to help readers navigate the changing landscape of web and mobile development.