In 1968, CACM published a letter from Edsgar Dijkstra, called “The GOTO Statement considered harmful”. In it, he explained why most bugs in a program were caused by gotos, and he appealed for goto to be expunged from programming languages. But Goto has a twin bother, which is responsible for nearly every bug that appears in programs today. In this session, Jules will revisit Dijkstra’s original explanations, and show why If and Goto have the same pathology. He will then go on to explain how to avoid this pathology altogether.