  Topcolor and topcolor-assisted technicolor provide examples of dynamical
electroweak symmetry breaking which include top-condensation, thereby naturally
incorporating a heavy top quark. In this note we discuss the roles of the
Nambu-Jona-Lasinio (NJL) and large-N approximations often used in
phenomenological analyses of these models. We show that, in order to provide
for top-condensation but not bottom-condensation, the top-color coupling must
be adjusted to equal the critical value for chiral symmetry breaking up to
O(1/N) in any theory in which the isospin-violating ``tilting'' interaction is
a U(1) gauge interaction. A consequence of these considerations is that the
potentially dangerous ``bottom-pions'' are naturally light. We also show that
the contributions to rho-1 previously estimated are of leading-order in N, are
not included in the usual NJL analysis, and are the result of
``vacuum-alignment''.
