This book provides the first theoretical interaction model of pen-and-paper user interfaces and an integrated set of interaction techniques for knowledge workers. The model proposes a ‘construction set’ of core interactions that are helpful in designing solutions that address the diversity of pen-and-paper environments. The interaction techniques, concrete instantiations of the model, provide innovative support for working with printed and digital documents. They integrate well-established paper-based practices with concepts derived from hypertext and social media.