This year, Cor van den Bleek turned 60. He also retired as Professor in Chemical Reactor Engineering at Delft University of Technology, to devote more time to his other passions in life. This Festschrift celebrates Prof. van den Bleek’s impact on chemical reaction engineering, in particular in the areas of multiphase reactors and environmental reaction engineering. Work during the last decade on gas–solid fluidization is a prime example of his technology-driven scientific research. It illustrates how seemingly abstract scientific concepts from chaos theory and non-linear analysis could be used in chemical engineering practice, to help describe, model, scale-up, monitor, and control multiphase reactors with complex fluid dynamics. Yet, more than this, it also illustrates the other drivers behind his research—fun and beauty. As Cor puts it: "I can only do research on what I truly enjoy". Professor van den Bleek’s influence is clear from the many colleagues who have promptly answered the call for papers for this special issue: Many who have directly or indirectly been inspired by Cor, who have collaborated or had intense scientific contact with him. We thank all the contributors for their excellent manuscripts, and the many reviewers for their thorough and critical reports, respecting strict deadlines without compromising on quality, in order to assemble a high-quality volume of recent research results in the course of only a few months. We are especially grateful to Elsevier, to the Editorial Board of Chemical Engineering Journal, and in particular to Prof. J. Santamaria, co-editor in charge of reaction engineering, for helping us to realize this Festschrift as a Special Issue of the Journal. Finally, the three of us have had the pleasure and special privilege to work in Cor’s group. We are much indebted to him, not just for his scientific and engineering insight, which is the basis for current and future research, but also for his inspiring personality, his enthusiasm, and his genuine kindness. From all the reactions we received to the realization of this Festschrift, it is clear that many around the world share this feeling. This issue is a tribute to Professor Cor van den Bleek, and to modern, sustainable chemical reaction engineering.