The mixing of the neutral B mesons and the violation of CP symmetry
in the B sector can be investigated at the Tevatron proton-antiproton
collider.  The most severe challenge that these measurements pose is tagging
the flavor of a B meson at production.  Here we present in detail the method
of same side tagging (SST), which is used to obtain a new measurement of the
B^0 mass difference Delta m_d = 0.446 +/- 0.057(stat) +0.034 -0.031(syst)
ps^-1.  The significance of SST and other tagging methods for physics during
Run II of the Tevatron is discussed.