Prepositions

Q. Dear Sir or Madam, I’m having a disagreement with a coworker on a particular subject, and as my CMOS is at home, I can’t go to it for a ruling. I’m arguing that the prohibition against ending a sentence with a preposition is an invalid injunction—one that often serves to confuse and befuddle the reader by forcing tortured and mangled word placements. She says that the “rule” must be followed. So, is it appropriate to end a sentence with a preposition? Thank you.

A. That old prohibition is a what we call a grammar superstition. You will not find it in any authoritative grammar book. Please see CMOS 5.176.