  We present the design of SCALES (Slicer Combined with Array of Lenslets for
Exoplanet Spectroscopy) a new 2-5 micron coronagraphic integral field
spectrograph under construction for Keck Observatory. SCALES enables
low-resolution (R~50) spectroscopy, as well as medium-resolution (R~4,000)
spectroscopy with the goal of discovering and characterizing cold exoplanets
that are brightest in the thermal infrared. Additionally, SCALES has a 12x12"
field-of-view imager that will be used for general adaptive optics science at
Keck. We present SCALES's specifications, its science case, its overall design,
and simulations of its expected performance. Additionally, we present progress
on procuring, fabricating and testing long lead-time components.
