Professor Andreas Alexandrou sadly passed away at the age of 60 on May 31, 2018, after a long battle with cancer. Contributors to this volume and others more generally involved in visco-plasticity and rheology will miss his free academic spirit and the warmth and optimism he conveyed to everyone fortunate enough to know him. Andreas was a well-liked member of the viscoplastic community. In fact, he is one of the few people who participated in all the “Viscoplastic-Fluids (VPF)” conferences, which started in 2005; he also co-organized the third one (VPF2009) in Limassol, Cyprus.