Crossword puzzle clue "one who may sign a book"

One who may sign a book

Good sign or bad sign

Warning sign at a train station's food court? (NOTE: The original sign, without my additions, actually exists. It's in Grand Central Terminal in NYC, on the lower level — the food court level. The sig

Sign of danger — sign of socialism

Pre-sign sign

One may close a book

One may be open-book

Sign-up book for races?