The anisotropy of arrival directions of cosmic rays above 10(17) eV

A detailed analysis of the world's data on ultra-high energy cosmic rays, w hich come from measurements of extensive air showers, reveals clear evidenc e for anisotropies in their arrival directions at energies below about 10(1 9) eV. Confidence in this conclusion comes from consistency, within the err ors, of the results from the different experiments and a correlation betwee n independent indicators of anisotropy. Although models of the Galactic magnetic field topology are not yet precise , we have used one such to estimate the fraction of cosmic rays which are l ight nuclei as a function of energy.