Biological physics, or the physics of living systems, has emerged fully as a field of physics, alongside more traditional fields of astrophysics and cosmology, atomic, molecular and optical physics, condensed matter physics, nuclear physics, particle physics, and plasma physics. This new field brings the physicist's style of inquiry to bear on the beautiful phenomena of life. The enormous range of phenomena encountered in living systems - phenomena that often have no analog or precedent in the inanimate world - means that the intellectual agenda of biological physics is exceptionally broad, even by the ambitious standards of physics.Physics of Life is the first decadal survey of this field, as part of a broader decadal survey of physics. This report communicates the importance of biological physics research; addresses what must be done to realize the promise of this new field; and provides guidance for informed decisions about funding, workforce, and research directions.