We have made 110 attempt to separate Leto's truths from his foibles or to indicate which is which. Such judgments are best left to scholars or to the general reading public at whom this book is aimed. In addition, Leto assembled much material from the centuries post-dating the Butlerian Jihad, and we present some of it in this book, including newly discovered information about the hitherto legendary Jehanne Butler who gave her name to the jihad she so nobly led. Thus some of the entries in The Dune Encyclopedia were written by people who actually lived at the time of Muad'Dib; others were prepared by contemporary scholars based upon older materials, and still other entries represent preliminary papers prepared by the many investigators at Dar-es-Balat.