Comprehensive review of key topics in root science, including root architecture, root growth regulators, root anatomy and nutrient acquisitionCoverage of root response to both biotic and abiotic variablesDiscusses the range of techniques to optimize root function, from phenotyping to identify desirable root traits and exploiting the genetics of root traits to the use of plant growth-promoting rhizobacteria (PGPR) and arbuscular mycorrhizal fungi (AM)