A superb guide to Sigil, particularly for the DM. If you want to know all about Sigil, you must get this book. It is full of detailed descriptions of the wards of the city and strongly conveys the atmosphere of this most unique place. There is no substitute for this book. Other sources like Uncaged: Faces of Sigil and the Faction War adventure provide additional information, but this book is the key guide to Sigil.