Plants convert inorganic nitrogen into amino acids, the building blocks for proteins. They also make a wide range of other nitrogen compounds to help protect themselves from pests and diseases. An understanding of these compounds can therefore help in devising better crop protection and production methods. This volume contains essays by scientists who have studied aspects of plant nitrogen nutrition and amino acid biosynthesis. There are chapters on protein amino acids, nonprotein amino acids, betaines, glutathione, polyamines, and other secondary metabolites derived from amino acids. The results of these studies will be of interest to graduate students and professionals in biochemistry and botany.