The discovery of the neutrino non-standard properties (mass and mixing) refocused on various aspects of the neutrino standard properties, both from the theoretical and the experimental side. In particular, precise measurements and modeling of the \nu -Nucleus Cross-Section in the {intermediate} energy range (\sim 0.5--5 GeV), and related Nuclear Effects, are now considered as fundamental issues. In fact, these become necessary for a more robust control of the systematic uncertainties relevant in the forthcoming experimental effort aiming at precision measurements of the MNSP matrix elements. A critical review of the present knowledge motivated the origin and the activity of a wide community progressively formed around these issues. In this introductory review we provide with a qualitative summary of the achievements from the current activity in this field.

PACS numbers: 13.15.+g, 14.60.Lm, 14.60.Pq