The sixth volume of the series "Physics and Evolution of the Earth's Interior" focuses on the mature evolution of the Earth's interior.

Three closely coupled branches of Earth sciences are presented. These are: paleomagnetism, plate tectonics and mantle convection theory. Their mutual connections are described and the mantle stresses driving the evolution processes are discussed. Paleomagnetism not just provides crucial data confirming the plate tectonics. In a similar way, plate tectonics gives the best evidence of the mantle convection process.

Mantle convection is a leading subject of the book. Both the observational and theoretical approach to mantle convection are presented. The observational approach includes the paleomagnetism backing the plate tectonics theory, methods of interpretation of the gravity data and seismic tomography. The motion of the lithospheric plates described by plate tectonics is a surface manifestation of the convective flow.

The gravity data, after some assumptions, could be a source of information about the density distribution in the mantle. This is of special value because the density distribution is included directly in the equation of motion for fluid.

1. The seismic tomography provides the data about distribution of seismic wave velocities and seismic anisotropy. Wave velocities data can be interpreted in terms of density distribution whereas seismic anisotropy data indicate the direction of convective flow.

Theoretical approach to the mantle convection includes educing the equations of fluid dynamics, mathematical methods for its handling and a review of the various convection models. The mantle convector is also a source of stresses in the lithosphere. This subject and coupled phenomena are also discussed in the volume. The other extensively discussed subjects are plate tectonics and paleomagnetism.

Another way of investigation of Earth's evolution is offered by thermodynamics of the irreversible processes.