It is with heavy hearts that we said goodbye to Papa Tavy this weekend. From growing up in Shanghai, to surviving World War 2, to marrying the wonderful Mary Jo, to lecturing across the world, to publishing textbooks that still sell today, to raising a beautiful family (I’m biased) and cracking jokes all the way to the age of 90. He lived an extremely full life, touched so many people, and will be sorely missed. He taught my brothers and I how to whistle and to love dogs. He has a programming language and a dutch society named after him, and at his retirement party the fax machine overflowed onto the floor with congratulations from students and colleagues around the globe. He was fiercely anti-computer (his Chemical Reactor Omnibook  is written by hand) and would probably garumph at this being typed online but I’ll miss you, Papa. Goodbye to an amazing human being.