An introductory survey on variational inequalities should have been made
here by G. Stampacchia.
All those of you who knew him, who had the pleasure to share with him
long and stimulating discussions, who knew his warm personality, will share
my emotion and my sorrow.
In what follows, I will try to present some of his main ideas and his main
contributions in the field of variational inequalities, the main topic of the
meeting mentioned in the preface and where he was looking forward to
participating and lecturing.
Therefore, I will not speak of his previous contributions; a general report
with a complete bibliography will be presented by E. Magenes in the
Bollettino dell'Unione Matematica Italiana.1
In the field of partial differential equations and functional analysis, in