The X-ray tomographic imaging research eﬀort at the University of Chicago is an integrated program of system design, hardware optimization, and image reconstruction advances. New developments in one area inform developments in the others, as when breakthroughs in image reconstruction theory make possible entirely new scanning geometries. Current research projects include development of advanced reconstruction algorithms allowing for high-quality images to be obtained from sparse, low-dose clinical data. Related algorithms have been used to design new imaging systems aimed at providing three-dimensional reconstructions of humans, animals, and specimens, and have also found applications in security scan, explosive detection, and non-destructive inspections. Another strand of work relates to the advancement of extremely high resolution CT using the Advanced Photon Source synchrotron at Argonne National Lab. This has produced fully three-dimensional images of entire organisms (zebraﬁsh) at cellular resolution as well as novel approaches to dual energy CT with heavy stains that we have called color x-ray histology.