No book has appeared since 1959 which summarized our insights in the nitrogen metabolism of plants. This book, therefore must be welcomed, as much research in this field has been published in recent years. Many new facts were discovered, new metabolic schemes were developed and new problems arose. This book fills the existing gap in an exellent way. In an introductory chapter on N-nutrition, processes like N2-fixation, nitrification and de-nitrification, NOj reduction and NH4 assimilation are discussed. Subsequently some chapters summarize our knowledge about the biochemistry of N-compounds, their synthesis and metabolism. In succession, reviews are given of amino acids, purines, pyrimidines, nucleosides and nucleotides, and proteins. The main biochemical reactions of synthesis and breakdown are summarized in surveyable schemes.