David Ellyard has been closely involved with science all his working life. He has been a researcher, teacher and government policy advisor, and for more than 30 years a science communicate, working in radio television and print. He was also President of the Australian Science Communicators. His previous publications include books on weather and astronomy, and a prize-winning biography of the controversial Australian physicist and public figure Sir Mark Oliphant. Who Discovered What When? combines his love of history with his deep concern for the human and social impacts of new ideas and inventions.