Leonard Frank Meares (13 February 1921 – 4 February 1993) was an Australian writer of western fiction. He wrote over 700 Westerns for the Australian paperback publishers Cleveland and Horwitz using the pseudonym "Marshall McCoy", "Marshall Grover", "Ward Brennan" and "Glenn Murrell".
Among his most famous characters were "Larry & Stretch", Larry Valentine and Stretch Emerson. In the United States (Bantam Books) they they were known as "Larry & Streak" (Larry Vance & Streak Everett)" and the in the Nordic countries they were known as "Bill & Ben".
Big Jim's horse Hank is killed on purpose and Jim goes after the killer, along the way teaming up with L&S, Doc Beaumont and Slow Wolf, which is the reason for the title! Oh, and there's also Benito.