From the introduction to the book:
Dark Despair is the second instalment of the Gathering Darkness Campaign. Unlike the previously released The Rising Shadow, this publication will present less background material and more adventure. The Pfeildorf: Freistadt of Sudenland sourcebook is a companion to Dark Despair, though a GM will not necessarily need the former to run the latter.
Background information accompanying this scenario can be found in the Appendices at the end. The information is intended for the GM's use, though she can elect to provide any or all of this to the Players as desired. For ease of use, a Player's version of the map is included in this manuscript.