  The role of background in bosonic quantum statistics is discussed in the
frame of a new approach in terms of coherent states. Bosons are indeed detected
in different physical situations where they exhibit different and apparently
unconnected properties. Besides Bose gas we consider bosons in particle physics
and bosons in harmonic traps. In particle physics bosons are dealt with in a
context where the number of observed particles is finite: here the relevant
features are the canonical commutation relations, which we shall show to be
related to a Boltzmann-like distribution. A further case is Bose condensate in
harmonic traps, where discrete spectrum leads us to predict, below T_c, a new
critical temperature. The unified approach proposed shows that all defferences
can be ascribed to the environment.
