Kai Lawonn has submitted his Phd thesis “Illustrative Visualization of Medical Data Sets” after a record time of 2 years and 4 months. As a mathematician, Kai soon become familiar with shader programming and advanced visualization techniques enabling him to make a number of strong contributions in illustrative and medical visualization. Among these contributions is a new method to generate smooth yet precise cutting lines based on an initial user-defined line, a substantial comparison of feature line techniques, the introduction of a new technique combining advantages of features lines and hatchings as well as improved smart visibility techniques to display vascular surfaces and embedded (simulated) blood flow. Also Kai was the first to display endoscopic views with feature lines and discussed pros and cons of their use.