Part I: Upper Mantle and Transition Zone -- Global Heterogeneity of the Lithosphere and Underlying Mantle: a Seismological Appraisal Based on Multimode Surface-wave Dispersion Analysis, Shear-Velocity Tomography, and Tectonic Regionalization -- Origin of Lateral Heterogeneities in the Upper Mantle Beneath Southeast Australia from Seismic Tomography -- Imaging Mantle Heterogeneity with Upper Mantle Seismic Discontinuities -- Interpreting Radial Anisotropy in Global and Regional Tomographic Models -- Relationships between Seismic Wave-Speed, Density, and Electrical Conductivity Beneath Australia from Seismology, Mineralogy, and Laboratory-Based Conductivity Profiles from Seismic Tomography -- Heterogeneity of Electrical Conductivity in the Oceanic Upper Mantle -- Melt-Pockets and Spongy Clinopyroxenes in Mantle Xenoliths from Plio-Quaternary Al Ghab Volcanic Field, NW Syria: Implications for the Metasomatic Evolution of the Lithosphere -- Elasticity of Continental Crust Around the Mantle Transition Zone -- Effect of Water on Subduction of Continental Materials to the Deep Earth -- Part II: Lower Mantle -- The Composition of the Deep Earth -- Chemical Geodynamics in a Non-Chondritic Earth -- Seismic Detections Of Small-Scale Heterogeneities in the Deep Earth -- Seismic Detection of Post-Perovskite Inside the Earth -- Thermally Dominated Deep Mantle LLSVPs : A Review -- Large-Scale Thermo-Chemical Structure of the Deep Mantle: Observations and Models. This book highlights and discusses recent developments that have contributed to an improved understanding of observed mantle heterogeneities and their relation to the thermo-chemical state of Earth's mantle, which ultimately holds the key to unlocking the secrets of the evolution of our planet. This series of topical reviews and original contributions address 4 themes. Theme 1 covers topics in geophysics, including global and regional seismic tomography, electrical conductivity and seismic imaging of mantle discontinuities and heterogeneities in the upper mantle, transition zone, and lower mantle. Theme 2 addresses geochemical views of the mantle including lithospheric evolution from analysis of mantle xenoliths, composition of the deep Earth, and the effect of water on subduction-zone processes. Theme 3 discusses geodynamical perspectives on the global thermo-chemical structure of the deep mantle. Theme 4 covers application of mineral physics data and phase equilibrium computations to infer the regional-scale thermo-chemical structure of the mantle. .