[ Hinkle / Blackjack ]
Blackjack, a work of fiction for young adult readers, was first published in 1946.
Thomas Clark Hinkle (1876 - 1949) was an American medical doctor and novelist, primarily of animal stories (often set in the American West) written for younger readers.
Blurb:
"Blackjack's mother was a huge black dog, probably part Newfoundland, and so Jack was also a huge dog. Clark Preston claimed Jack as his own and the pair did a lot of hunting together. Wild dogs were a menace to the cattlemen in the area and Blackjack proved that he could stand up to any of them on the day of reckoning."