IAS, Bât. 121, Université de Paris XI, 91405 Orsay Cedex, France
This paper reviews what we know on the Extragalactic Background (EB) and on the nature of its contributing galaxies in the infrared (IR) and sub-millimeter (sub-mm). I first present the EB observationnal constraints, their main cosmological implications, and results from deep IR and sub-mm surveys. Then, using a phenomelogical model of IR galaxy evolution, I show how these data constrain the evolution of IR galaxies, in particular the luminosity density and the luminosity function. And finally, I briefly review the detection of the IR EB fluctuations and their potential implications.
(Online publication September 25 2002)