This festschrift contains essays dedicated to Hartmut Ehrig, on the occasion of his sixtieth birthday. Ehrig’s methods originated in category theory, and were first applied in a graph-theoretic context. Now, they are omnipresent. Appropriately, this festschrift shows their influence across a broad range of fields, including concurrency modeling, state charts, coalgebras, and Petri nets, and exemplifies them in such areas as molecular biology and systems theory for transportation.

The book contains 24 contributions by 44 authors (many of them widely known, with only a few appearing repeatedly), and is divided into three sections: “Graph Transformation,” “Algebraic Specification and Logic,” and “Formal and Visual Modeling.” The book also contains Ehrig’s impressive bibliography, with six books authored, 17 books edited, and 238 papers published. The volume allows the worldwide and highly interrelated group-forming work of Ehrig to be observed. The essays are carefully balanced--some are highly technical, others are explanatory texts, and some are reports on supporting systems.