B-bar{B} Mixing and b Hadron Lifetimes from Lattice QCD

We discuss neutral B_{s,d} meson mixing and b-hadron lifetimes from the perspective of recent lattice calculations. In particular, we consider matrix elements which can be combined with measured \Delta M_{s,d} to constrain |V_{td}|, the lifetime ratios \tau(\Lambda_b)/\tau(B_d) and \tau(B^-)/\tau(B_d) and the lifetime difference, \Delta\Gamma_s/\Gamma_s, in the neutral B_s meson system.