We present the final band-merged ELAIS Catalogue at 6.7 , 15 , 90 , and 175 \mu m , and the associated data at U , g ’ , r ’ , i ’ , Z , J , H , K , and 20cm .
The origin of the survey , infrared and radio observations , data-reduction and optical identifications are briefly reviewed , and a summary of the area covered , and completeness limit for each infrared band is given .
A detailed discussion of the band-merging and optical association strategy is given .
The total Catalogue consists of 3762 sources .
23 \% of the 15 \mu m sources and 75 \% of the 6.7 \mu m sources are stars .
For extragalactic sources observed in 3 or more infrared bands , colour-colour diagrams are presented and discussed in terms of the contributing infrared populations .
Spectral energy distributions ( seds ) are shown for selected sources and compared with cirrus , M82 and Arp220 starburst , and AGN dust torus models .

Spectroscopic redshifts are tabulated , where available .
For the N1 and N2 areas , the INT ugriz Wide Field Survey permits photometric redshifts to be estimated for galaxies and quasars .
These agree well with the spectroscopic redshifts , within the uncertainty of the photometric method ( \sim 10 \% in ( 1+z ) for galaxies ) .
The redshift distribution is given for selected ELAIS bands and colour-redshift diagrams are discussed .

There is a high proportion of ultraluminous infrared galaxies ( lg _ { 10 } of 1-1000 \mu m luminosity L _ { ir } > 12.22 ) in the ELAIS Catalogue ( 14 \% of 15 \mu m galaxies with known z ) , many with Arp220-like seds .
10 \% of the 15 \mu m sources are genuine optically blank fields to r ’ = 24 : these must have very high infrared-to-optical ratios and probably have z > 0.6 , so are high luminosity dusty starbursts or Type 2 AGN .
9 hyperluminous infrared galaxies ( L _ { ir } > 13.22 ) and 9 EROs ( r-K > 6 ) are found in the survey .
The latter are interpreted as ultraluminous dusty infrared galaxies at z \sim 1 .
The large numbers of ultraluminous galaxies imply very strong evolution in the star-formation rate between z = 0 and 1 .
There is also a surprisingly large population of luminous ( L _ { ir } > 11.5 ) , cool ( cirrus-type seds ) galaxies , with L _ { ir } - L _ { opt } > 0 , implying A _ { V } > 1 .