In this, the sixteenth entry in the long-running series of Mr. & Mrs. North mysteries penned by husband and wife writing team Richard and Frances Lockridge, a noted palaeontologist published by Jerry North’s firm is being harassed by means of fake ads in newspapers claiming he wishes to hire, e.g., tree surgeons, the ads resulting in constant disruptions as the scientist works on his next book. Things look more serious when a guest at his apartment is poisoned by the milk, but when he is later found dead — under circumstances that indicate suicide — neither Pam nor Jerry North is able to let the case alone. Plenty of suspects and a well-crafted climax in a darkened museum make this one work quite well. Recommended.