EDS, a REDUCE package for exterior differential systems. The EDS package for symbolic analysis of partial differential equations using the geometrical approach of exterior differential systems (EDS) is described. The package implements much of exterior differential systems theory, including prolongation and involution analysis, and has been optimized for large, nonlinear problems. Besides the description of the facilities in the package, two nontrivial sample calculations arising from general relativity are presented (Source: http://cpc.cs.qub.ac.uk/summaries/)