This is the first Dr. Thorndyke novel, from 1907, one of the earliest forensics-based mysteries. A valuable shipment of diamonds goes missing from a safe, and a nice young man is put in the dock for it. As evidence mounts, a renowned forensics expert is called in to help with the defense. The plot twists are easily guessed, the characters speak in a mildly stilted manner that reflects their class(es) and origins, and the forensics seem extremely basic to us now, but this was one of the earliest and still holds up. The writing is smooth, the obligatory love story not intrusive, the forensics solid and well-presented, and the characters of Dr. Thorndyke and Dr. Jervis are likable and seem real.
You can see the debt Freeman owed Doyle, and the one owed to him by Sayers and numerous others. Thorndyke has a "man" named Poulton who is, at the least, Bunter's very useful Uncle, and Jervis is pretty nearly "son-of-Watson", including the love story. Thorndyke is extremely Holmesian, withholding almost all information until the denouement, rationalized as being legal discretion, but still used for good effect at the end. The courtroom scene is wonderful.
The net result is an enjoyable reminder of how life - and mysteries - used to be. (Abbey)