Agricultural systems have developed from a research tool in agricultural biology to a discipline that encompasses the whole of the food chain and into institutional and extended education. In this book the current state of agricultural systems is summed up by 14 figures who each deal with their particular specialities. The definitive summaries are now available in book form having been prepared for a conference to commemorate the retirement of a pioneer of agricultural systems, Colin Spedding. The first section deals with the techniques used to develop understanding of plants, animals and the interactions between the two. The book then goes on to discuss systems covering research allocation of the enterprise and farm level, the development of food markets, agricultural strategy formation and insititutional and extension education. Following on from the present state of development each contributor tries to predict the direction which the subject will take in the future.