In the Standard Model of Particle Interactions, the basic building blocks of matter are six leptons and six quarks that interact by means of force-carrying particles called bosons. Every phenomenon observed in nature can be understood as the interplay of the fundamental particles and forces of the Standard Model. But physicists know that the Standard Model does not tell the whole story, and they are searching for physics beyond the Standard Model that will lead to a larger, more elegant "theory of everything."