Before you is a vast collection of information relating to various sides and aspects of The Dune Chronicles, including scientific topics and just interesting little things. Undoubtedly, some of the articles in the Encyclopedia will cause a lot of heated discussions, because they themselves are based on sources that are by no means indisputable. Others, on the contrary, will put an end to protracted speculation. Experts have done serious work, trying to uncover issues related to geology, biology, astronomy and mythology; as well as with the pronunciation of words, biographies of the main characters, various stories and information about little-known figures. The range of topics covered is wide: from games for fun to games with life and death (from pyramidal chess "Cheops" to "Assassin's Handbook"). The history of the Financial Synod, which later gave birth to KOOAM, the public will be able to read for the first time on the pages of the Encyclopedia. In fact, it highlights many of the mysteries hidden in The Dune Chronicles. How did Irulan and Ghanima's mutual resentment begin? Who is Jehanna Butler, and why is Butlerian Jihad named after her? What are the secrets of the origin of the Space Guild? Where were cosmogation techniques using the melange trance state discovered and developed? What was Leto II's personal opinion regarding Saint Sister Quintinius Violet Chenow? Does Cheops have anything to do with the three-body problem? I must admit that I found it extremely fascinating to be able to take a fresh look at some of the sources from which I drew material for the creation of The Dune Chronicles. As a first-time Dune fan, I give this Encyclopedia my enthusiastic approval, even though I still have my own intention to continue to explore some of the problematic issues in the further development of Chronicles. Frank Herbert Port Townsend, Washington November, 1983