You can absolutely tell that this book was published in 1938. It is not one of Stout's best.

Part of Stout's aim here was undoubtedly to highlight for his readers the way racial prejudice operated in the American South in the late 1930s. Despite this good intention, I don't feel like those sections really stand up very well in terms of story. (Having a luxury spa in 30s West Virginia seems a little forced, for starters.)

Stout's characterization of the victim's wife is straight out of femme fatale noir.

For those who wish to totally avoid racial slurs: this book does contain them. They are to the best of my recollection "appropriately" used—I mean the characters who use them would use them—and Nero Wolfe does not.

Still, in my opinion even "not the best" Nero Wolfe stories are worth reading. But maybe just move on to the next one when you're done.