  The B factories were constructed with a very specific purpose in mind: to
test the Cabibbo-Kobayashi-Maskawa description of quark mixing and CP violation
in the Standard Model of particle physics. The goals of testing this part of
the Standard Model were achieved, and have been surpassed beyond all
expectation. As a result the B factories have revolutionised our understanding
of many areas of the Standard Model of particle physics, and also provide a
number of stringent limits on possible scenarios of physics beyond the Standard
Model. In some cases these limits on new physics effects equal or surpass those
achievable at the CERN based Large Hadron Collider.
