Van der Waals (vdW) interactions are ubiquitous in all materials. The influence of vdW forces extends beyond binding energies into the structural, mechanical, spectroscopic, and electronic signatures of condensed matter. Our conceptual understanding of these interactions is based on perturbative models, which are unable to capture the full extent of quantum-mechanical fluctuations which can extend up to tens of nanometers in real materials . The origin of such many-body fluctuations will be discussed and their importance demonstrated for dimers, supramolecular complexes, semiconductors, to layered 2D heterostructures. The development of efficient many-body methods that explicitly address the collective nature of quantum fluctuations leads to significant improvements in the accuracy of calculations [2,3,4], and enables control of these fluctuations in the design of intricate materials.  Science 351, 1171 (2016).  Phys. Rev. Lett. 108, 236402 (2012).  Adv. Func. Mat. 25, 2054 (2015).  Chem. Sci. 6, 3289 (2015).