The global Knowledge Society requires comprehensible technical texts (e.g. process descriptions, requirements specifications, minutes, forms). Linguistic comprehensibility research in collaboration with Cognitive Science and new disciplines such as Information Design and Usability Engineering can make valuable contributions towards an integrated understanding of understandable texts, which are getting more and more multimodal. In this book, different approaches and disciplines are brought together into a frame model of text comprehensibility, which claims to be scientifically sound as well as comprehensible and applicable for practitioners. The final part of the book provides three extensive case studies of applications: Legal texts, technical writing, and software development.