  The ionizing continuum shape of quasars is generally not directly observable,
but indirect arguments, based on photoionization models and thin accretion disk
models suggest that it should peak in the extreme UV, and drop steeply into the
soft X-ray regime. However, recent observations of very soft X-ray emission in
low z quasars, and far UV emission of high z quasars, suggest that the ionizing
continuum of quasars does not peak in the extreme UV, and may extend as a
single power law from ~1000 A to ~1 keV. If true, that has interesting
implications for photoionization models and for accretion disk models. The
proposed revised continuum shape will be tested directly in the near future
with FUSE.
