Professor Underwood is a world authority on the experimental ecology of coastal marine habitats. His work is widely cited as original and rigorous. Much of it has been adopted as the inspiration for novel initiatives by other ecologists, both within and outside marine ecology. He has published extensively on the design of ecological experiments, on sampling designs to detect environmental disturbances, and on the relationship between the philosophy and logic of quantitative ecology on the one hand and the detection and management of environmental problems on the other. He has supervised 50 postgraduate students, has published more than 100 papers, and has been a major initiator of increased rigour in Australian and international ecology.