In my opinion, Dufour's book is the definitive account of the New Orleans Campaign although some had disagreed with his conclusion. There is no doubt that the fall of the city was a major blow to the Confederacy but calling it the reason the Confederacy lost may be a stretch. Dufour was a journalist but did thorough research. Chester Hearn has done a book on the campaign that, in my opinion, is not nearly as good and seems to have borrowed heavily from Dufour's work (to the point of repeating a misspelling that appeared in one of Dufour's notes).