Has Anyone Seen Heather? has all the ingredients of the well-made mystery novel, or thriller. Suspense builds upon suspense, mystery upon mystery, as one plot becomes entangled with another. Clare and Katie struggle hard to keep their grandfather from learning that Heather has not met them at Euston Station after all, even as they try to discover from him if she has sent word to them there. A strong antipathy develops between the sisters and Mrs. Hanna, the housekeeper who looks after Mr. Livingstone, Heather's invalid former employer, and they suspect her of sending the threatening letters; more, Katie even suspects her of stealing the painting that Heather allegedly took. The French professor becomes a sinister if shadowy presence in the novel, bringing a police investigator to the William Shakespeare to interrogate Clare. Meanwhile, Clare is afraid for her mother as well as for her sister...