This volume pays tribute to the scientific achievements of Hartmut Ehrig, who passed away in March 2016.

The contributions represent a selection from a symposium, held in October 2016 at TU Berlin,  commemorating Hartmut' s life and work as well as other invited papers in the areas he was active in.

These areas include Graph Transformation, Model Transformation,  Concurrency Theory, in particular Petri Nets, Algebraic Specification, and Category Theory in Computer Science.