Gate of Horn, Book of Silk, is organized in two parts, with the first half covering the Long Sun series (Nightside the Long Sun, Lake of the Long Sun, Caldé of the Long Sun, and Exodus from the Long Sun) and the second half covering the Short Sun series (On Blue's Waters, In Green's Jungles, and Return to the Whorl). "Languages of the Whorl," a section between the two parts, covers all the dialect, slang, and foreign terms used in the books--thieves' cant, flier language, Tick's talk, and more. Ten maps and diagrams are included.
This is Michael Andre-Driussi's third guidebook to the rich tapestries of Gene Wolfe's worlds. As fans of of Lexicon Urthus and The Wizard Knight Companion have noted, that each book is both a convenient tool for a question while re-reading the novels but also an enjoyable read in its own right, from A to Z.