Some theoretical aspects of $B$ physics are reviewed. These include a brief recapitulation of information on weak quark transitions as described by the Cabibbo-Kobayashi-Maskawa (CKM) matrix, a description of CP asymmetries in $B$ decays to CP eigenstates and self-tagging modes, a discussion of final-state phases in $B$ and charm decays, some topics on $B_s$ properties and decays, the prospects for unusual excited $B$ states opened by discovery of some narrow $c \bar s$ resonances, and the prospects for seeing the heavier $Q=1/3$ quarks predicted in some extended grand unified theories.

23 pages, LaTeX, 12 figures, invited talk presented at Fourth Tropical Workshop, Cairns, Australia, 9--13 June 2003. Proceedings to be published by AIP. Some updated figures