Published online by Cambridge University Press: 04 October 2008
We summarize the main highlights from ISO observations towards Sgr B2 and Orion KL in the far–IR domain (~43 to 197 μm). Both Star–Forming Regions are among the best sources to construct a template for more distant and unresolved regions (e.g., extragalactic). We stress some peculiarities in the interpretation (excitation and radiative transfer) of far–IR spectral lines and dust continuum emission.