SPIRE: The bolometer camera and spectrometer for FIRST

We describe the science goals and outline design for the I SPIRE instrument to be launched on the ESA cornerstone mission FIRST. SPIRE is a bolometer insrtument covering the wavelength range 200-670 microns and will have three imaging channels centred at approximately 250, 350 and 500 microns, along with a broad-band imaging Fourier transform spectrometer operating from 200-670 microns. The photometer will observe the same 4x8 arminute field of view with each channel with diffraction-limited angular resolution (18 arcseconds at 250 microns). The spectrometer will have a field-of-view of at least 2 x 2 arcminutes and will have spectral resolution adjustable from approximately 20 to 1000. The detector arrays will operate at 0.3 K. The primary science gods are deep extragalactic and galactic surveys for high-redshift galaxies and young protostellar sources respectively and follow-up spectrophotometric observations.