Cosmic Ray Antiprotons

Cosmic ray antiprotons have been detected for over 20 years and are now measured reliably. Standard particle and astrophysics predict a conventional spectrum and abundance of secondary antiprotons consistent with all current measurements. These measurements place limits on exotic Galactic antiproton sources and non-standard antiproton properties. Complications arise, particularly at low energies, with heliospheric modulation of cosmic ray fluxes and production of standard secondaries from A > 1 nuclear targets. Future experiments and theoretical developments are discussed.