  NASA's Great Observatories have opened up the electromagnetic spectrum from
space, providing sustained access to wavelengths not accessible from the
ground. Together, Hubble, Compton, Chandra, and Spitzer have provided the
scientific community with an agile and powerful suite of telescopes with which
to attack broad scientific questions, and react to a rapidly changing
scientific landscape. As the existing Great Observatories age, or are
decommissioned, community access to these wavelengths will diminish, with an
accompanying loss of scientific capability. This report, commissioned by the
NASA Cosmic Origins, Physics of the Cosmos and Exoplanet Exploration Program
Analysis Groups (PAGs), analyzes the importance of multi-wavelength
observations from space during the epoch of the Great Observatories, providing
examples that span a broad range of astrophysical investigations.
