**1. Introduction**

In the 1960s, Orson Anderson established a new laboratory at Columbia University's Lamont Geological Observatory and chose to name it "Mineral Physics." Experiments in his laboratory measured mineral properties over the wide range of pressures, temperatures and chemical compositions seen in the interior of Earth and other terrestrial planets. These studies included properties of minerals, but all materials related to natural minerals (e.g., structural analogs, but also glasses, melts and fluids). According to Robert Hazen [1], "mineral physics is the study of mineralogical problems through the application of condensed matter physics". In reality, mineral physicists use not only physics but also solid-state chemistry. Knowledge of these properties is essential to interpretations of seismic data accurately and performing realistic geodynamic simulations. Today, mineral physics is widely considered one of the three pillars of geophysics, along with geodynamics and seismology.

Today, scientists approach these problems through a combination of experimental and computational methods. Precise information at lower pressures and temperatures is provided by experiments, and detailed information at conditions difficult to recreated in the laboratory is provided by computational work. Bulk material properties are vital to understanding the behavior of planets, but atomistic inspection of these complex materials provides a connection to planetary-scale phenomena. Theoretical mineral physicists are in a unique to position to illuminate this connection [2] (see also paragraph by Taku Tsuchiya below).

In the past half century since the first scientific conference focused on mineral physics was held in 1977, mineral physics has matured into an independent scientific discipline firmly in the mainstream of geosciences. Now mineral physicists are faced with many challenging problems and many exciting opportunities for research; in large measure, this is now possible due to access to synchrotron X-radiation facilities throughout the world. This evolution is highlighted in this chapter (see also our earlier paper [3]).
