Margaret Redfern has been interested in plant galls for most of her adult life. After graduating in 1963, she studied part-time for higher degrees while teaching natural history and ecology to sixth formers, undergraduates and adult amateurs, first for the Field Studies Council and later at Portsmouth, Birmingham and Sheffield Universities. Her MSc research involved the natural history of thistle galls, and her PhD covered a population study of the yew gall midge. This research became a long-term project lasting forty years, forming the longest continuous data set on a gall insect, and probably on any insect, anywhere in the world. She continues to teach degree students at Sheffield University and to investigate the natural history of galls. She has published several books and papers, all of them on galls.

Most of us have noticed galls as bizarre and often colourful distortions of plant growth, and wondered what goes on inside them. The drama enacted within a single gall may involve many species of insects and mites.