It has been estimated that more than twelve billion tons of concrete are produced worldwide each year. By far the mostpervasive and affordable building material in the world, concrete has undergone ever-more-widespread dissemination, standardization, and technological innovation in the last twenty-five years. Recent scientific breakthroughs have yielded composites stronger than steel, lighter than water, and as beautiful as natural stone. In Solid States, an interdisciplinary group of architects, historians, theorists, engineers, fabricators, and materials scientists collectively explore the past, present, and future possibilities of this highly calibrated, fluid material. Solid States presents new theoretical and cultural analyses of concrete architecture, both historically and in the context of newly built work.