Roth, Holly -- Operation Doctors (1962)

(aka Too Many Doctors)

A more classical-type detective story than we have come to expect from Holly Roth, which gets off to a very promising start but sadly flounders into incoherence by the end. 

The German merchant vessel MS Tilburg is sailing on her regular run from Southhampton to the Far East  with fifty passengers and a similar complement of crew. On the first day a woman falls -- or is pushed -- down a flight of stairs and put to bed in her cabin, badly injured. She appears to lose her memory as a result, and since the passenger list includes a Max Owings, an American neurosurgeon, he is asked to examine her in company with the ship's own doctor. Meanwhile in London, a doctor has been killed and another one has disappeared. When a corpse fished from the Thames is found to found to have a stethoscope in its pocket the events are linked, and Inspector Medford is sent to meet the Tilburg at Genoa and explore its connection with this medical mystery.

Unfortunately the connection turns out to be highly coincidental and insanely complicated, and the smoothly-running plot runs off the sliprails and sinks funnel-deep into farce. But the book is worth reading for its earlier promise.

Jon.