The Hero of this story is Alexander Short, a Reference Librarian at the New York Public Library. Alexander's job is to mostly take "call slips" from members of the public who request books from the stacks. He does a few other jobs as well such as telephones and the front desk, depending on the senior Librarian's mood. And because Alex is not a conservator, he is banned from the Conservation Room.
He has a number of quirks, one of which is collecting call slips with interesting examples of penmanship. Another quirk is "Girdling" - a notebook on a string tied to his wrist or his jacket - in which he jots down (in an old form of shorthand) anything that he thinks is unusual. He also likes enclosures and mechanical things such as timepieces.
One day he is asked by an elegant man (Henry James Jesson III) with very elegant penmanship on the call slip, to retrieve a book from the stacks called the Secret Compartments in Eighteenth Century Furniture. It is a book on false fronts and secret recesses.
Alexander is drawn into Jesson's desire to find the object that was once housed in a drawer of a small glassfronted display box. The object turns out to be a timepiece. But not just any timepiece. The Queen. The Marie Antoinette. One of a kind.
The only trouble was, Marie Antoinette never got to hold her watch because it was not completed until after she was beheaded. The watch later ended up in a Museum in Jerusalem. In 1983 it was stolen from the museum and has never been seen or heard of since. The book goes into a lot of detail (too much detail in my opinion) over the theft from the Museum, how it was done, and why other vandalism was done at the same time.
Jesson's all consuming desire to find the watch affects Alex, and thus begins to affect Alex's marriage as well. Anyway, Alexander eventually discovers that he has been manipulated by Jesson into finding the watch, and he turns the tables on Jesson, and walks away to save his marriage.
The entire story was a search for a magnificant watch. The background was the New York City Public Library. I loved all the Library details. The ending was somewhat of a disappointment. Never mind that the watch has never been found for real. I would have liked Alex to have found it.