A Typesetter's Dream

This is a cryptic crossword, though the word at 17 Across is unclued. Discovering this word will tell you why this puzzle is so special. Download the puzzle file and have at it! If you don't know what cryptic crosswords, check out http://solving-cryptics.com/. Don't read the answer file until you are done (or you give up on a clue). Good luck and we hope you have fun!