Professor Stephen Powles foresaw that herbicide resistance would become a great problem in Australian and world agriculture. He pioneered resistance science, integrating molecular to agronomic initiatives in Australia, and became the international authority on herbicide resistance. He unravelled several resistance mechanisms including sequestration and metabolism. He first documented resistance glyphosate, the world’s most important herbicide. He showed that individual resistant plants simultaneously expressed several resistance mechanisms, endowing multiple resistance to most herbicides on earth. He contributes greatly to the management of herbicide resistance and GM crops and communicates approaches to industry, crop consultants, farmers and scientists around the world.