Pressure is a key parameter in manufacturing, physical sciences, and life sciences in defining the state of matter. In this issue of MRS Bulletin, we focus on several of the many and diverse domains of advanced materials research where applied pressure (or stress) is used to alter, or otherwise garner information on, material properties. We give an overview of research in which the application of high pressure—often combined with high temperatures and advanced analysis—has led to technological progress, such as in the preparation of superhard materials, in discovering new chemistry for dense forms of low-Z elements, and in the interplay and mimicking of chemical-induced versus pressure-induced structural and electronic changes to prepare new magnetic and energy materials. In addition, the response of materials such as glasses and perovskites to high-stress conditions is discussed, where pressures in the gigapascal regime can easily be achieved in everyday usage. Finally, the structural, dynamical, and phase behavior of biological systems under pressure is explored.