The Cube Builder for IRS Spectra Maps (CUBISM), is a tool for constructing spectral cubes, maps, and arbitrary aperture 1D spectral extractions from sets of mapping mode spectra taken with Spitzer's IRS spectrograph. It is optimized for non-sparse maps of extended objects, e.g., the nearby galaxy sample of SINGS, but can be used with data from any spectral mapping AOR (primarily validated for maps which are designed as suggested by the mapping HOWTO). CUBISM was developed by the SINGS team to fulfill, in part, its Legacy proposal commitments.