  We give an introduction to the dynamical symmetry breaking with large
anomalous dimension. This is the basis of tightly bound composite Higgs models
such as walking technicolor, strong ETC technicolor and top quark condensate,
which are all characterized by the large anomalous dimension, \gamma_m \simeq 1
(walking technicolor), 1<\gamma_m<2 (strong ETC technicolor) and \gamma_m
\simeq 2 (top quark condensate) due to nontrivial short distance dynamics of
the gauged Nambu-Jona-Lasinio (NJL) models (gauge theories plus four-fermion
interactions). Particular emphasis will be placed on the top quark condensate
in which the critical phenomenon in the gauged NJL model yields a simple reason
why the top quark can have an extremely large mass compared with other quarks
and leptons. Topics will also cover a recent observation that the four-fermion
theory {\it in the presence of gauge interactions} (gauged NJL model) can
become renormalizable and nontrivial in sharp contrast to the pure NJL model
without gauge interactions. The requirement of this
renormalizability/nontriviality of the gauged NJL model can be applied to the
top quark condensate when the standard gauge groups are unified into a GUT with
``walking'' coupling, which then naturally leads to the top quark and the Higgs
masses both around 180 GeV.
