Genetics of Root Hair Formation -- Intracellular Organization: A Prerequisite for Root Hair Elongation and Cell Wall Deposition -- Auxin and Root Hair Morphogenesis -- The Membrane Dynamics of Root Hair Morphogenesis -- Plant Cell Wall Biogenesis During Tip Growth in Root Hair Cells -- Modeling Tip Growth: Pushing Ahead -- Root Hair Electrophysiology -- Calcium in Root Hair Growth -- Phospholipid Signaling in Root Hair Development -- ROP (Rho-Related Protein from Plants) GTPases for Spatial Control of Root Hair Morphogenesis -- The Actin Cytoskeleton in Root Hairs: A Cell Elongation Device -- Microtubules in Plant Root Hairs and Their Role in Cell Polarity and Tip Growth -- Nod Factor Signal Transduction in the Rhizobium-Legume Symbiosis -- Architecture of Infection Thread Networks in Nitrogen-Fixing Root Nodules -- Microbial Encounters of a Symbiotic Kind: Attaching to Roots and Other Surfaces -- Root Hair Colonization by Mycorrhizal Fungi. Root hairs, the tip-growing extensions of root epidermal cells, are a model system for answering many plant cell and developmental biology research questions. This book, written by experts in the field, covers the research up to 2008 on cellular, genetic, electrophysiological and developmental aspects of root hair growth, as well as the interaction of root hairs with rhizobia and mycorrhizae in the establishment of symbiosis. With a wealth of information on technical and experimental aspects useful in the laboratory, this comprehensive book is a valuable resource for researchers and students in the broad field of plant cell and molecular biology.