Eliot Paul, Waylaid in Boston: A Homer Evans Mystery
Coachwhip Publications, 2016 (reprint of 1953 original)
Homer Evans and Finke Maguire (Finke is a PI in LA, Evans is…well, it's not clear quite what he is) are in Boston on a more-or-less vacation. One evening, over drinks, one of their group of friends, acquaintances, and hangers-on proposes a bet: That an ordinary citizen could not undertake to follow someone and attempt to discover things about him, without making a hash of it. Obviously, the bet is accepted, and what ensues can justifiably be called a catastrophe. The book does have, however, a rather neat money-laundering scheme applicable (in this case, to Argentina) for people trying to get money out of a country with stringent currency controls. Paul wrote a lot, and, if this is typical, it's perhaps unsurprising that he is not well-remembered.