The American Physical Society (APS) is a not-for-profit membership organization of professionals in physics and related disciplines, comprising nearly fifty divisions, sections, and other units. Its mission is the advancement and diffusion of knowledge of physics. The society publishes more than a dozen scientific journals, including the prestigious Physical Review and Physical Review Letters, and organizes more than twenty science meetings each year. APS is a member society of the American Institute of Physics. Since February 2015 the organization is led by chief executive officer Kate Kirby.