This novel is an excellent example of the inverted detective story, a modern form that R. Austin Freeman is credited with inventing.
The fun comes not from being baffled, but from watching Thorndykes mind at work and observing his scientific methods which include, in this case, geology, petrology, psychology, marine biology, handwriting analysis, and chemical analysis. The victim is a boorish, overbearing, dishonest brute with money.
The murderer is a likable, gentlemanly, talented artist of modest means.