  Two topics in heavy quark expansion are discussed. The heavy quark potential
in perturbation theory is reviewed in connection to the problem of the heavy
quark mass. The nontrivial reason behind the failure of the "potential
subtracted" mass in higher orders is elucidated. The heavy quark sum rules are
the second subject. The physics behind the new exact sum rules is described and
a simple quantum mechanical derivation is given. The question of saturation of
sum rules is discussed. A comment on the nonstandard possibility which would
affect analysis of BR_sl(B) vs. n_c is made.
