Book excerpt: This volume explores several different aspects of nitrogen metabolism, ranging from nitrogen uptake to assimilation. The chapters in this book cover topics such as measurement of activities of enzymes involved in nitrogen metabolism (i.e., nitrate reductase); measurement of nitric oxide, nitrite and ways to detect the N content in plants and microbes; characterization of root nodule bacteria (RNB); and techniques to perform proteomics of Extracellular Matrix (ECM). Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Thorough and cutting-edge, Nitrogen Metabolism in Plants: Methods and Protocols is a valuable tool for novice and expert researchers who are interested in learning more about this evolving field.