''The Death That Lurks Unseen'' is Fletcher's early masterpiece in the mystery and crime fiction genre. At this stage in his career, Fletcher was blending his journalistic precision with a flair for atmospheric, psychological narrative, featuring enigmatic protagonists and exploring dark human impulses, hidden truths, and moral ambiguity.

Notable characters in this tale include a "strange creature"—a gaunt, middle-aged man with fierce eyes and a long beard—who is desperately searching for something he lost.

The reader gets a sense from reading ''The Death That Lurks Unseen'' that it is one of J. S. Fletcher's best mystery thrillers—so tightly written, not overly long, yet it feels complete and so satisfying.