Having read just about all of the Nero Wolfe series, I have to say, this one contains all of the elements that make Rex Stout's detective novels wildly entertaining, without most of the elements that make some of them maddening
In this mystery, the utterly unswashbuckling Wolfe is revealed, in his younger, svelter days, to have been quite a romantic. Not only did he fight on the anti-Imperial side in Montenegro during the Great War, but he adopted and may even have actually sired a young girl.
To his shock, this young Yugoslav maiden--whom he had lost track of--reappears in his life, up to her neck in a particularly messy, intricate affair that may or may not include missing diamonds, a dead body or two, international intrigue, and a bellboy's uniform. For all of the peeks into Wolfe's previously unsuspected soul, he remains as crumudgeonly and as immovable as ever. Archie Goodwin, of course, remains the wisecracking, milk-drinking sidekick, flirting with anything in a skirt and even giving a Nazi agent a black eye just for the fun of it.
The joy of these books is their marriage of the American gumshoe attitude and the British cozy focus on character. Where they generally fall short is their plotting. This entry in the series is, without a doubt, the most successfully rounded out of the lot. Stout manages to keep the mystery truly mysterious, and yet never manages to confuse the reader so thoroughly that s/he can't find the exit. The plot actually ends on the last page--many of the Nero Wolfe mysteries fizzle out, wrapping up a chapter or two before the end, leaving nothing but rumination and grumbling for the final pages. Others seem never quite to wrap up all the loose ends. Here, the conclusion is both inevitable and unexpected--utterly satisfying.