Professor Peter Sly is an acknowledged pioneer in understanding the early origins of lung disease and the implications for lung health in the long term. He has discovered major risk factors for the development of asthma and for the onset of cystic fibrosis lung disease, leading to a number of testable hypotheses to prevent or delay the onset of lung disease, which are currently being trialled internationally. He has been instrumental in developing methods for measuring lung function in infants which enable for the first time the study of antenatal versus postnatal environmental influences on lung growth and development. Peter Sly is at the forefront of international thinking on the prevention of lung disease in children.