  Thanks to its unprecedented sensitivity and large field of view, XMM occupies
a leading position as a survey instrument. The XMM-LSS survey is a medium-deep
large-area X-ray survey, and greatly extends the cosmological tests attempted
using earlier studies. While a wealth of complementary multiwavelength studies
are taking place, I concentrate here on the XMM-EPIC data, describing aspects
of the X-ray pipeline and analysis, and selected first results, including the
deepest wide-angle X-ray image of the cosmos to date.
