  Strutinsky's method is reviewed through a new understanding. This method
depends on two free parameters: The smoothing parameter and the order of the
curvature correction. It turns out that this method is nothing but a compromise
between two fundamental conditions which are the so-called asymptotic limit
which comes from the so-called remainder which imposes a small as possible
smoothing parameter and the smoothing condition which forces that parameter to
be, at least, slightly larger than the inter shell spacing. In this paper, to
find the best value of the smoothing parameter, a new criterion is proposed
instead of the plateau condition . This new criterion is much more clear and
free from ambiguities of the usual plateau condition. It is also found, that
the second free parameter, i.e., the order of the curvature correction, plays
an accessory role since, it is connected intimately to the smoothing parameter,
when the smoothing is realized. This paper provides a new and definitive
insight into Strutinsky's method and its relationship with semi-classical
methods.
