  The class of Super Soft Sources has been established after discoveries
performed with the Einstein and the ROSAT satellite. Only sources contributing
to the class of super-soft X-ray binaries are considered. The X-ray emission in
these sources is due to thermonuclear burning of accreted material on the
surface of a white dwarf. The physical process of nuclear burning is described.
The typical timescales of variability in these sources are discussed. The
appearance and modeling of supersoft X-ray spectra are described. The phenomena
related to the accretion disk in these sources are outlined. A discussion of
the nature and appearance of the donor star is given. The evolutionary state of
these sources and their likely progenitorship for Type Ia supernovae is shortly
outlined. A summary of recent discoveries with Chandra and XMM-Newton of
super-soft sources in nearby spiral and elliptical galaxies is given.
