Very few mathematicians manage to transcend the boundaries of more than one mathematical discipline and make substantial contributions to several areas of Mathematics. Jon was undeniably one of them. He was a paragon of Experimental Mathematics, Functional Analysis, Optimization and other areas. His research work has already inspired thousands of individual researchers and will remain as a testament to this generation and to the coming ones. [Ilias Kotsireas, Wilfrid Laurier University, Canada]