Electron Paramagnetic Resonance (EPR) Volume 21 highlights major developments in this area, with results being set into the context of earlier work and presented as a set of critical yet coherent overviews. The topics covered describe contrasting types of application, ranging from biological areas such as EPR studies of free-radical reactions in biology and medically-related systems, to experimental developments and applications involving EPR imaging, the use of very high fields, and time-resolved methods. Critical and up-to-the-minute reviews of advances involving the design of spin-traps, advances in spin-labelling, paramagnetic centres on solid surfaces, exchange-coupled oligomers, metalloproteins and radicals in flavoenzymes are also included. As EPR continues to find new applications in virtually all areas of modern science, including physics, chemistry, biology and materials science, this series caters not only for experts in the field, but also those wishing to gain a general overview of EPR applications in a given area. Volume 21 cover literature published during 2005 and 2006.