"Van der Waals (vdW) interactions are ubiquitous in nature, playing a major role in defining the structure, stability, and function for a wide variety of molecules and materials. VdW forces make the existence of molecular liquids and solids possible; they largely control protein-protein and drug-protein binding inside our bodies; they give geckos the ability to “defy gravity” attaching to walls and ceilings. An accurate first-principles description of vdW interactions is extremely challenging, since the vdW dispersion energy arises from the correlated motion of electrons and, in principle, requires many-electron quantum mechanics. Rapid increase in computer power and advances in modeling of vdW interactions have allowed to achieve “chemical accuracy” (1 kcal/mol) for binding between small organic molecules. However, the lack of accurate and efficient methods for large and complex systems hinders truly quantitative predictions of properties and functions of technologically relevant materials. We aim to construct and apply a systematic hierarchy of efficient methods for the modeling of vdW interactions with high accuracy and capacity to predict new phenomena in complex materials. Starting from quantum-mechanical first principles (adiabatic-connection fluctuation-dissipation theorem), we unify concepts from quantum chemistry (linear-response coupled-cluster and many-body perturbation theory), density-functional theory (ground-state electron-density response), and statistical mechanics (coupled-fluctuating-dipole model). Our final goal is to enable long time-scale molecular dynamics simulations with predictive power for large and complex systems of thousands of atoms. The project goes well beyond the presently possible applications and once successful will pave the road towards having a suite of first-principles modeling tools for a wide range of materials, such as biomolecules, nanostructures, solids, and organic/inorganic interfaces."