Bose-Einstein Interference and Factorization at High Energies

We consider the emission or absorption of $n$ identical bosons from an energetic or a massive particle, in which the bosons and the source particle are allowed to be offshell. The Bose-Einstein symmetrized amplitude can be decomposed into sums and products of more elementary objects which we choose to call `atoms'. The origin of this decomposition, its significance and some of its applications will be summarized.