Part I Biochemistry and Molecular Biology Toolbox.- Chapter 1 Isolation, Identification and Biochemical Characterization of Azospirillum spp. and other Nitrogen-Fixing Bacteria.- Chapter 2 Molecular Tools for Identification and Characterization of Plant Growth Promoting Rhizobacteria with emphasis in Azospirillum spp.- Chapter 3 In situ Localization and Strain-Specific Quantification of Azospirillum and other Plant Growth Promoting Rhizobacteria Using Antibodies and Molecular Probes.- Chapter 4 Molecular Tools to Study Azospirillum sp. and other Related Plant Growth Promoting Rhizobacteria.- Chapter 5 Genomic Tools for the Study of Azospirillum and other Plant Growth Promoting Rhizobacteria.- Part II Physiology and Metabolism Toolbox.- Chapter 6 Chemotaxis and other Forms of Taxis Behaviors in Azospirillum spp.- Chapter 7 Phytohormones and other Plant Growth Regulators Produced by PGPR: The Genus Azospirillum.- Chapter 8 Inorganic Nitrogen Metabolism in Azospirillum spp.- Chapter 9 Nitric Oxide in Azospirillum and Related Bacteria: Production and Effects.- Chapter 10 Cell Aggregation, Attachment and Plant Interaction.- Chapter 11 Methods for Studying Biofilms in Azospirillum and other Plant Growth Promoting Rhizobacteria.- Chapter 12 Methods for Studying Phenotypic Variation in Azospirillum.- Chapter 13 Polyhydroxybutyrate in Azospirillum brasilense.- Chapter 14 Siderophores Production by Azospirillum: Biological Importance, Assessing methods and Biocontrol activity.- Chapter 15 Cell-Cell Communication in Azospirillum and Related Plant Growth Promoting Rhizobacteria.- Chapter 16 Methods to Study 1-Aminocyclopropane-1-Carboxylate Deaminase in Plant Growth Promoting Bacteria.- Chapter 17 Production of Volatile Organic Compounds in Plant Growth Promoting Rhizobacteria.- Chapter 18 Stress Physiology in Azospirillum and other Plant Growth Promoting Rhizobacteria.- Part III Biotic Interactions Toolbox.- Chapter 18 Alleviation of Abiotic and Biotic Stresses in Plants by Azospirillum.- Chapter 19 Interaction of Azospirillum spp. with Microalgae: a Basic Eukaryotic–Prokaryotic Model and its Biotechnological Applications.- Chapter 20 Pseudomonas and Azospirillum.- Chapter 21 Co–inoculation of Legumes with Azospirillum and Symbiotic Rhizobia.- Chapter 22 Interaction of Azospirillum and Mycorrhiza.- Part IV Agronomic and Industrial Applications Toolbox.- Chapter 23 Field Evaluation of Extensive Crops Inoculated with Azospirillum sp.- Chapter 24 Azospirillum spp. and Related Plant Growth Promoting Rhizobacteria Inocula Use in Intensive Agriculture.- Chapter 25 Inoculant Preparation and Formulations for Azospirillum spp.- Chapter 26 Protocol for the Quality Control of Azospirillum spp. Inoculants.