  The origin of the highest energy cosmic rays represents one of the most
conspicuous enigmas of modern astrophysics, in spite of gigantic experimental
efforts in the past fifty years, and of active theoretical research. The past
decade has known exciting experimental results, most particularly the detection
of a cut-off at the expected position for the long sought
Greisen-Zatsepin-Kuzmin suppression as well as evidence for large scale
anisotropies. This paper summarizes and discusses recent achievements in this
field.
