  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.
