String theory is a theoretical framework which was proposed to produce a unified description of all particles and forces in nature, including gravity. It is based on the idea that at very short distances, all particles should in fact be seen to be extended one-dimensional objects, i.e., ‘strings.’ Modern string theory has grown to be a broad and varied field of research with strong connections to quantum gravity, particle physics and cosmology, as well as mathematics. An exciting new framework known as ‘holography’ has emerged from string theory whereby quantum gravity is formulated in terms of quantum field theory in one less dimension. This symbiosis between quantum field theory and quantum gravity has been a focus of many Perimeter researchers. This has led to the development of exciting new methods to study the quantum dynamics of gauge theories and in the application of these techniques to new domains, such as nuclear physics and condensed matter physics.