  We give a linking theorem that strengthens and unifies some many minimax
theorems including Ambrosetti-Rabinowitz ``mountain pass theorem'', Rabinowitz
``multidimensional mountain pass theorem'', Rabinowitz ``saddle point theorem''
and Silva's variants of these results.
  We focus our attention especially on ``the limiting case'', known to be true
for the mountain pass principle, where some information on the location of the
critical points is given. Two forms of this theorem are given: the first one is
established via a deformation lemma and we use Ekeland's variational principle
to get the second one.
