... about Ed Reid or Ovid Demaris... nor how much of the book they may have made up...
but according to Wikipedia, Ed Reid did have a fairly impressive career as a reporter...

Ed Reid (1915 - 1977) was an author and investigative journalist who exposed organized
crime in New York City and Las Vegas. He was born in Manhattan and grew up in Brooklyn.
Reid started as a reporter in 1935 and used his writing to fight corruption.

An eight-part series published in 1949 by the Brooklyn Eagle exposed the activities of
bookmaker Harry Gross and corrupt members of the New York City Police Department.
This exposé led to an investigation by the Brooklyn District Attorney’s office and resulted in
the eventual resignation of New York City Mayor William O'Dwyer.

In the 1950s and early 1960s, Reid worked at the Las Vegas Sun. His investigative
reporting exposed the hidden ownership interest of mobsters Jake & Meyer Lansky in
the Thunderbird Hotel. Reid, with Ovid Demaris, co-authored The Green Felt Jungle, a
New York Times Best Seller for 23 weeks in 1964, which exposed greed and depravity
in Las Vegas.

The book connected then Senator Barry Goldwater to labor racketeer Willy Bioff causing
Goldwater to threaten a libel suit against the publisher. Reid was dismissed from the
Las Vegas Sun by publisher Hank Greenspun after he wrote The Green Felt Jungle.

Ed Reid’s reporting for the Brooklyn Eagle earned him the 1951 Pulitzer Prize for
public service along with numerous other awards.