This note contains spoilers for the book.

Early detective novel. Dr. Thorndyke practices forensic medicine, and gets involved in mysteries.

This one has a nice scene where they X-ray the mummy and discover the secret, including processing the sheets of paper (they couldn't get film that big) in the darkroom.

There's a sub-plot involving a strange will, and conflict between relatives over who gets the inheritance. The solution is elegant, really; the body will be preserved in the district wanted, in a place approved for such use. It's just, it'll be disguised as an ancient Egyptian mummy on display in the museum, rather than being conventionally buried.