Philip W. Anderson (1923–2020) is widely regarded as one of the most accomplished and influential physicists of the second half of the twentieth century. Educated at Harvard, he served during World War II as a radar engineer, and began a thirty-five year career at Bell Laboratories in 1949. He was soon recognized as one of the pre-eminent theoretical physicists in the world, specializing in understanding the collective behavior of the vast number of atoms and electrons in a sample of solid matter. He won a one-third share of the 1977 Nobel Prize for Physics for his discovery of a phenomenon common to all waves in disordered matter called Anderson localization and the development of the Anderson impurity model to study magnetism. At Cambridge and Princeton Universities, Anderson led the way in transforming solid-state physics into the deep, subtle, and coherent discipline known today as condensed matter physics. He developed the concepts of broken symmetry and emergence and championed the concept of complexity as an organizing principle to attack difficult problems inside and outside physics. In 1971, Anderson was the first scientist to challenge the claim of high-energy particle physicists that their work was the most deserving of federal funding. Later, he testified before Congress opposing the Superconducting Super Collider particle accelerator. Anderson was a dominant figure in his field for almost fifty years. At an age when most scientists think about retirement, he made a brilliant contribution to many-electron theory and applied it to a novel class of high-temperature superconductors.