Almost half a century has passed since the first satellite experiment, which exploited the polarization dependence of Bragg reflection from graphite crystals, flew aboard NASA’s Orbiting Solar Observatory number 8. I will discuss, on behalf of the entire IXPE team, a new NASA Small Explorer mission performed in collaboration with the Italian Space Agency. IXPE, scheduled for launch in late 2021, will be much more powerful than the instrument aboard OSO-8 and uses a very different technology. Using advanced detectors developed in Italy, the detectors image the track of charge resulting from the photoelectron produced in the initial interaction of an incident X-ray with the gas in an imaging proportional counter. The initial direction of the charge track depends directly on the position angle of the polarization. Coupling the detectors with X-ray optics to render the background essentially negligible results in a polarimeter that can produce time and/or energy, and/or spatially resolved polarization-dependent images of the brighter and most interesting X-rays sources, namely neutron stars and black holes. We present an overview of IXPE, its capabilities, laboratory measurements that have supported its development, and calibration. We include highlights of several astrophysically important and unique experiments.