How to become a successful tool builder - the dirty tricks Gerd Behrmann Aalborg University Abstract: Although we all love playing with tools, tool development is often considered less valuable or is less respected than theory development. At many universities, developing and releasing a tool is not even counted as a scientific contribution. I will argue that tool development is not only a valuable and important activity, but an essential part of a scientific approach to the area of algorithmic verification. At the same time, empirical studies in this field are often of questionable quality, with results that are not reproducable and unfounded conclusions. This situation must be improved if tool building shall become a respected activity.