Explaining the science contained in a simple assembly of grains—the most abundant form of matter present on Earth. Granular media—composed of vast amounts of grains, consolidated or not—constitute the most abundant form of solid matter on Earth. Granular materials assemble in disordered configurations scientists often liken to a bag of marbles. Made of macroscopic particles rather than molecules, they defy the standard scheme of classification in terms of solid, liquid, and gas. Granular materials provide a model relevant to various domains of research, including engineering, physics, and biology. William Blake famously wished “To See a World in a Grain of Sand”; in this book, pioneering researchers in granular matter explain the science hidden behind simple grains, shedding light on collective behavior in disordered settings in general. The authors begin by describing the single grain with its different origins, shapes, and sizes, then examine grains in piled or stacked form. They explain the packing fraction of granular media, a crucial issue that bears on the properties displayed in practical applications; explore small-scale deformations in piles of disordered grains, with particular attention to friction; and present theories of various modes of disorder. Along the way, they discuss such concepts as force chains, arching effects, wet grains, sticky contacts, and inertial effects. Drawing on recent numerical simulations as well as classical concepts developed in physics and mechanics, the book offers an accessible introduction to a rapidly developing field. “This eye-opening book provides a view into the staggering scientific, practical, and historical importance of seemingly simple, dirty, and mundane particulate matter. The authors demonstrate in diverse examples how major insight across scales and disciplines can be gained from careful study of grains and the structures they form.” —Daniel I. Goldman, Dunn Family Professor of Physics, Georgia Institute of Technology   “Granular matter is chimeric—not quite a fluid or a solid, and yet both. This charming scientific account, woven together with strands of history and culture, reminds us of how the commonplace is anything but.” —L. Mahadevan, de Valpine Professor of Applied Mathematics and Professor of Physics and Organismic and Evolutionary Biology, Harvard University   “An immensely readable journey into the world of granular matter, where fascinatingly complex behavior emerges from even the simplest of objects once crowded together in large number.” —Heinrich Jaeger, Professor of Physics, University of Chicago Étienne Guyon is Emeritus Professor at ESPCI (Paris Industrial Physics and Chemistry Higher Educational Institution), a fellow of the American Physical society and of the Institute of Physics, Honorary Director of the Ecole Normale Supérieure, and coauthor of Built on Sand: The Science of Granular Materials (MIT Press). He works at the PMMH (Physics and Mechanics of Heterogenous Media) lab of ESPCI-PSL in Sorbonne Université. Jean-Yves Delenne is Director of Research at INRAE (the French National Research Institute for Agriculture, Food and Environment). He is a pioneer in research on advanced numerical simulations of granular materials. Farhang Radjai is Director of Research at the CNRS (the French National Center for Scientific Research). He is a pioneer in research on advanced numerical simulations of granular materials.