Fuller, Roy. The Second Curtain (Harmondsworth, England: Penguin, 1976, c1953) 191 p.

A magazine editor looking to solve a mystery goes to the London Library. When it turns out they won't tell him who checked out a book he simply calls on the telephone claiming to be a police detective. Then he gets the information. Later in the same library he has a spooky feeling he is being followed in the stacks.

Here, only thick iron grids divided the rooms from the floor beneath. As he wandered along, switching the section lights on and off, he became aware that underneath someone else was walking, following a parallel course. He stopped dead in the alley of books: in the comparative quiet that followed he heard a clank or two from the shoes of the man below on his grids, and then there was complete silence. (p. 123).

The editor escapes from the library but is badly frightened by the event.