  The Mid-infrared ELT Imager and Spectrograph (METIS) will provide the
Extremely Large Telescope (ELT) with a unique window to the thermal- and
mid-infrared (3 - 13 microns). Its single-conjugate adaptive optics (SCAO)
system will enable high contrast imaging and integral field unit (IFU)
spectroscopy (R~100,000) at the diffraction limit of the ELT. This article
describes the science drivers, conceptual design, observing modes, and expected
performance of METIS.
