Understanding mantle dynamics is fundamental for the study of the solid Earth. However, there are still many challenges for investigating mantle dynamics due to the inaccessibility of the Earth's interior and uncertainties in observations, models, and experiments. Progress in measuring seismic anisotropy has generated new constraints on mantle dynamics, including crustal and lithospheric deformation, mantle circulation, subduction zone dynamics, core-mantle boundary processes, and crystallization in the inner core. Computational infrastructure advances have enabled Earth process simulations of unprecedented resolution. Recent experimental advances are leading to new constraints on the deformation and rheology of Earth materials at relevant temperatures and pressures. We welcome submissions on seismic anisotropy and how it relates to the dynamics of the solid Earth. Contributions from geophysical and geological observations (including seismic studies, MT measurements, and microstructural analyses of natural samples), geodynamics, and experimental and computational constraints on rheology and deformation are encouraged.