It has been our goal in assembling this volume to produce an overview of the composition, structure, and evolution of the Earth's mantle that will be authoritative, up-to-date, and forward-looking, yet thoroughly readable. It is our hope that it will prove useful to all those interested in the Earth's mantle and its workings, from beginning graduate students to experienced researchers. The volume consists of 11 chapters contributed by the staff of the Research School of Earth Sciences at the Australian National University and their collaborators, arranged into three parts, as follows:

Accretion and Differentiation of the Earth

Dynamics and Evolution of the Earth's Mantle

Structure and Mechanical Behaviour of the Modern Mantle

Recent progress towards consensus on many of the major issues surrounding the composition, structure, and evolution of the Earth's mantle makes this volume particularly timely. This Preface is intended to provide the reader a brief connected account of the topics addressed in this volume, not necessarily in their order of appearance, and an indication of the general philosophy adopted in assembling the material.

It is now widely accepted that the planet Earth was accreted from a hierarchy of planetesimals that formed in our solar nebula over a range of radial distances from the Sun. Through studies of chondritic meteorites, which display uniform relative abundances of refractory elements and systematic depletions of volatile species, the bulk composition of the silicate Earth can be constrained, albeit within significant residual uncertainties, especially in the important Mg/Si/Al ratios.