Don’t Know Tough Mysterious Book Report No. 489 by John Dwaine McKenna Don’t Know Tough, (Soho Crime, $24.95, 336 pages, ISBN 978-1-64129-345-7), by Eli Cranor,  is the apex of Southern Noir.  Placed in Denton, Arkansas, it’s hard-boiled, gut-wrenching, poignant, gritty, emotional, brutal, savage, raw, and stunningly authentic.  It’s a novel  you’ll never forget, and it’s hard to believe that it’s Mr. Cranor’s debut.  He speaks with authority and his