Seismology in polar regions (Arctic and Antarctic) allows us to study the static condition and high-latitude dynamics of the Earth. This book covers the recent developments in seismology in polar regions; observations and networks; international collaboration; heterogeneous structure and dynamics of the lithosphere; deep Earth's interiors observed from high latitudes; characteristics of seismicity and seismic wave propagation; and global tectonics in terms of Earth's history, including the interdisciplinary studies on the interaction between Earth's spheres. Since the International Polar Year (IPY) in 2007/2008 was the most exciting campaign launched within contemporary polar studies, this book observes recent seismological achievements by the IPY, specifically focusing on the seismic signals near the surface associated with cryosphere dynamics and evolution. Topics on cryoseismology, such as glacial earthquake activities, are viewed in terms of global warming. Moreover, observational experiments and long-term monitoring under the extreme conditions in the polar environment are also discussed.