This book is from the 1930’s. It’s that favorite: a closed circle mystery, complete with missing wills, servants, and an odd-lot family, few of whom are likable. So it’s pretty standard in the setup.
I’m fairly sure this is meant to be a parody of the genre and the trope. The main character/narrator, Peter Coffin (oh brother) seems at first to be a rather limp college professor but turns out to be an athlete and brave to the point of lunacy.
The book gets off to an extremely slow start, even for me. Things do pick up along the way as the investigation heats up and another murder occurs. So as a narrative and as a pleasant time-filler, this book works well.
But the characterization is really weak. People change behaviors and attitudes with no motivation. It’s disconcerting at best. And the police are treated like ignorant fatheads.
Read this only if you love mysteries from between the wars. Keep in mind that this isn’t a British story; it takes place in the US Midwest. ( )

divertente
qualche trascuratezza qua e là ma nel complesso è godibilissimo e in certi passi persino divertente