Contents: (1) Why bother with ultra-high-energy cosmic rays? (2) Observational data: Energy spectrum and composition of high-energy particles. Observed anisotropy of high-energy cosmic rays. Specific identified sources of cosmic rays. (3) Acceleration mechanisms: Problems associated with statistical acceleration. Direct acceleration. Final comments. (4) Propagation of cosmic rays: Propagation from extragalactic sources. Propagation from galactic sources. (5) Conclusions.