In this book, the author provides an insight into the behaviour of the Greylag Goose by describing his technique of imprinting the goose at hatching to make it believe that he was its parent and thus gain a valuable insight into its life. The text is peppered with the author's views on animal behaviour in general and human behaviour in particular, views that have caused considerable controversy in his field, but which led to Lorenz winning the Nobel prize for Medicine in 1973.