Among dozens of John Dickson Carr novels read during the last few months, for some reason this one stands out as a curiosity. It is clearly not as good as many other Carr books, perhaps owing to the author's declining health at the time (1968, a good 30 years after Carr's prime years of output). At the same time, there's more than enough of what was best about Carr in here to recommend it.
Real-life Senator Judah P. Benjamin serves as the central "detective" if not the protagonist of a murder mystery set in New Orleans a few years before the start of the American Civil War. As usual in his historical novels, Carr researched the time and setting well, thus providing a nicely atmospheric backdrop (with a dash of voodoo for creepiness). The characters are diverse and reasonably well-drawn for the genre, although often histrionic in matters of the heart, an element common to several Carr novels. If the means of murder is unspectacular, the murderer's motive is interesting both in a dramatic sense and for the way Carr fictionally places it within the actual history of famous (and scandalous) New Orleans residents. Carr's Notes For The Curious at novel's end illuminate what interested the author about his subject matter. Even so, Carr often takes his time getting to any point here. Like Old Man River, the story alternately meanders and rushes through its turns.
While this is nowhere near the best place to start with John Dickson Carr's novels, it might be that it's the best of Carr's last, which would also make it a good place to end a foray into the works of a master of detective fiction.