"USA - Großmacht unter dem Sternenbanner" ("USA - World Power under the Star Spangled Banner") is a german exclusive source book for the Cthulhu RPG published by Pegasus Spiele.
It contains an enormous amount of information on the United States of America in the 1920s. The most important cities are described in detail. A heavy topic lies on typical culture, every days life, society and arts. Gun, transportations, prohibition, law enforcment, crime, the Native Americans, legends, myths and last but not least Lovecraft country are more but not all the points covered by this book.