In this book, the authors have gathered and present current research from across the globe in the study of the structure, properties and dynamics of the Earth's core. Topics discussed include computer modelling of liquid iron solutions in the Earth's core; the origin and development of cores of the terrestrial planets from their tectomagmatic evolution and paleomagnetic data; the Slichter modes and their free translational oscillations of the inner core; manifestations of upwelling mantle flow on the Earth's surface and various geophysical data and theoretical models dealing with the behaviour of liquid and solid Earth's cores.