This book constitutes the refereed proceedings of the 9th InternationalConference on the Theory
and Application of Diagrams Diagrams 2016 held in Philadelphia PA USA in August 2016. The
12 revised full papers and 11 short papers presented together with 5 posters were carefully
reviewed and selected from 48 submissions. The papers are organized in the following topical
sections: cognitive aspects of diagrams logic and diagrams Euler and Venn diagrams diagrams
and education design principles for diagrams diagrams layout.
