The Men and Women of the "Sporting Fraternity" were all skilled players, meaning they could work wonders with cards or dice. Many times they were referred to as "Artists" because of the magic they could perform. Does that mean all professional gamblers were cheaters? No, but they had to know how to work the cards in order to overcome someone who was cheating.
A professional gambler could not stake his future on Lady Luck. He had to learn every move a crooked gambler could and would use in order to survive. When he sat down at a table with fellow professional gamblers each would make their best moves in order to come out on top. It was not only customary, it was necessary.
Men like Mason Long , J. H. Green and Kid Canfield, who were "accomplished" gamblers in their time, but eventually found a new calling and exposed the shady side of gambling in books they authored.
Long's book titled; The Life of Mason Long, the Converted Gambler was first published in 1878. Green wrote two books; The Reformed Gambler and the Secret Band of Brothers. Canfield's book titled, The Reformed Confidence Man and Gambler was published in 1911.