For 150 years scientists at the Rothamsted Experimental Station have studied aspects of plant nitrogen nutrition and amino acid biosynthesis. This book is the result of a meeting held to mark this century and a half of work there. The papers look at the significant progress in understanding the biochemistry of amino acids recently achieved, in the light of this history of research. Leading researchers from around the world have contributed authoritative chapters on protein amino acids, non-protein amino acids, betaines, glutathione, polyamines and other secondary metabolites derived from amino acids. As well as being essential in some animals' nutrition, these compounds can have important roles in defending against herbivores, insects and disease. An understanding of these compounds can help in devising better crop protection and production methods.