Astronomy and astrophysics at sub millimeter wavelengths

The still mostly unexplored sub-millimetric spectral domain contains great promises for a variety of astrophysical areas, and offers particularly exciting perspectives in the cosmological context. This is illustrated by the fact that it includes the Wien region of the Cosmic Microwave Background (CMB) as well as the most intense extragalactic background, the Cosmic Infrared Background (CIRB). During the last few years a variety of observational campaigns in the far-IR/sub-mm have started to provide results of strong cosmological impact, exploiting both ground-based and space instrumentation. All this is producing a revolution in the knowledge of the distant universe. Based on these first results, it is easy to anticipate that this new astronomy will play a major role during the next decades in unveiling the fundamental processes ana evolutionary steps through which the universe evolved from its initial simple conditions (as pictured in the CMB) to the highly differentiated and complex present scenario. It has been here briefly reviewed fields of observational cosmology which could mostly benefit from improved capabilities in the sub-millimeter band, with some attention to areas of specific interest for the italian groups