The Case of Cabin 13 by Sam McCarver, Signet 1999 mass market paperback, mystery novel, first printing, signed with signed bookmark. This is the first Professor John Darnell mystery.
“Passengers are dying on White Star Lines transatlantic ocean liners: three mysterious suicides, on three different ships, all in first-class cabins numbered 13.
With the maiden voyage of their newest ship imminent — an incomparably lavish vessel called the Titanic — the cruise line can’t afford a fourth. Professor John Darnell, the world’s first and only paranormal detective, may be their last hope of debunking rumors of a murderous ghost.
As the world’s largest and purportedly safest ship sets sail, neither Darnell’s sixth sense nor his investigative skills can protect him from the twin perils he is about to face.” – review on Goodreads
this paperback lived in a box for a few years before I took it out to read. The Titanic angle drew me in, but the mystery itself is pretty pedestrian. This is the first in a series.