The European Large Area ISO Survey: ELAIS

I describe a European collaborative project to survey \sim 20 square degrees of the sky at 15\micron and 90\micron with ISO. This is the largest open time project being undertaken by ISO. The depth and areal coverage were designed to complement the various Guaranteed Time surveys. The main science thrust is to explore star formation in galaxies to a much higher redshift than was probed by IRAS. We expect to detect around 8000 extra-galactic objects and a similar number of Galactic sources. The maps and source catalogues will represent a major legacy from ISO, inspiring follow up work for many years to come.