This document discusses responsive web design (RWD) for libraries. It defines RWD as a web design approach that provides an optimal viewing experience across different devices by adapting the layout. The document reviews examples of RWD library websites and compares RWD to mobile apps. It also discusses information architecture and how to design effective navigation, labels, and organization of content for users. Useful tools for developing RWD sites include MobileTest.me, RWD Calculator, Simple Grid, Gridpak, Skeleton, Bootstrap and others.