Mycorrhizal symbioses are central to the multitrophic interactions that impact plant productivity, competitiveness and survival. This book integrates present-day knowledge from well-known research groups on some of the topics which are at the forefront of mycorrhizal research. Topics include the cell programmes that drive mycorrhiza formation and function, the processes sustaining symbiotic mutualism, stress response mechanisms in mycorrhizal symbionts, and the diversity and ecological impacts of mycorrhizal systems. The efficient management of mycorrhizal systems has the potential to support the sustainable production of quality foods while ensuring environmental quality for future generations.