We dedicate this special issue to the memory of Wade Jacoby, the great scholar and wonderful friend whose works have inspired us, who played a major role in the birth of the project that lead to these papers, who was a careful reader of this collection and who, after having found two dozen problems per page in our papers and suggesting ways to fix them, still took the time to suggest another ten “problems of lesser importance” on those same pages. Wade was a great innovator in several fields who offered new tools for understanding pressing problems of our times, a dedicated mentor of younger colleagues and a superb companion admired for his modesty and his uncommon wit and wisdom.
