It has recently been demonstrated that there are strongly irreducible
subshifts of finite type with more than one measure of maximal entropy
. Here we obtain a number of results concerning the uniqueness of the
measure of maximal entropy. In addition, we construct for any d greate
r than or equal to 2 and k a strongly irreducible subshift of finite t
ype in d dimensions with exactly k ergodic (extremal) measures of maxi
mal entropy. For d greater than or equal to 3, we construct a strongly
irreducible subshift of finite type in d dimensions with a continuum
of ergodic measures of maximal entropy.