Because I liked Christopher Pena's flawed but informative Touched By War: Battles Fought in the Lafourche District (and its revised and expanded reissue Scarred By War: Civil War In Southeast Louisiana) well enough, I decided to try his latest work General Butler: Beast or Patriot - New Orleans Occupation May-December 1862. Although the research effort in Touched by War and Scarred by War was adequate, the author failed to consult a number of collections of unpublished source materials. The revised edition improves upon this to some degree. Unfortunately, this follow up effort, a history of Butler's stint in the Big Easy, leaves more than a bit to be desired.
General Butler: Beast or Patriot is far too dependent on secondary sources, mainly Chester Hearn's When the Devil Came Down to Dixie: Ben Butler in New Orleans and biographer James Parton's General Butler in New Orleans. History of the Administration of the Department of the Gulf in the Year 1862. The author admits that the Hearn book serves as a blueprint for his work, but I don't believe Pena adds enough original research in Beast or Patriot to allow the book to stand confidently on its own. Perhaps it can serve as a useful general introduction to the subject--a distillation of the current state of research--but individuals with a more serious interest in Butler's stay in New Orleans would certainly be better served to consult works that consistently cite original sources.