Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 169. Ultra-Low-Frequency (ULF) waves pervade the magnetosphere, a region shaped by the Earth"s magnetic fieid and filled with an ionized gas known as plasma. As a mechanism for interaction of particles with fields and as a diagnostic tool for probing the structure of the magnetosphere, ULF waves are a rich medium for research and discovery. With new spacecraft and computer simulations, and ground-based magnetometers and radar networks, we have recently expanded our capacity to analyze ULF waves on a global scale with unprecedented precision. Magnetospheric ULF Waves: Synthesis and New Directions presents state-of-the-art information on ULF waves, and their effect on space weather, from three vantage points:Excitation and propagationInteraction with plasma and energetic particlesMagnetospheric diagnosticsScientists, researchers, and students working in space physics, magnetospheric physics, atmospheric physics, climatoiogy and aeronomy will find this book an important resource for current and near-future investigations of the Sun-Earth relationship.