[2] Friedman came to the attention of the public when he published an exposé of anti-union actions by the private detective industry which was called The Pinkerton Labor Spy.
Friedman was called as a witness at the trial of the Secretary-Treasurer of the Western Federation of Miners (WFM), Big Bill Haywood.
The Idaho Daily Statesman described the Russian-born Friedman as, ... a striking looking young fellow, rather languid ... with a shock of black hair, and his features of the marked Hebrew type.
Pinkerton Agent George W. Riddell, former president of the Eureka miners union in Utah, was forced to resign when Friedman published the book.
Many reporters thought that the witness's testimony indicated "...that many of the infiltrators were actually agents provocateurs who'd committed crimes to bring the unions into disrepute.