Potter’s Field Mysterious Book Report No. 348 by John Dwaine McKenna Three years ago, a new writing talent appeared and lit up the hard-boiled crime scene like machine-gun fire on a moonless night.  The author’s name was Rob Hart, and his character, Ash McKenna, is a tough guy who—like Raymond Chandler’s Phillip Marlowe—gives bad-assiveness a good name.  Happily, he’s now back in his fifth adventure. Potter’s Field, (Polis Books,