| A | B |
|---|
| Buck | a very large, intelligent dog |
| Judge Miller | Buck's owner in California |
| Manuel | The Judge's gardener's helper who steals and sells Buck to pay off gambling debts |
| Man in the Red Sweater | Member of the stolen-dog ring who teaches Buck that "a man with a club is a lawgiver" |
| Perrault and Francois | Two French Canadians who are Buck's first masters in Alaska |
| Scotchman | Buck's second master who delivers mail to gold seekers in the North |
| Charles | One of Buck's foolish and inexperienced American masters |
| Mercedes | Charles's wife |
| Hal | Mercedes's brother, a headstrong, cruel man |
| John Thornton | Man who rescues Buck from the Americans and teaches Buck true love |
| Hans and Pete | John Thornton's partners |
| Matthewson | Man who bets that Buck can't pull a thousand-pound load |
| Jim O'Brien | Man who lends Thornton a thousand dollars to bet on Buck |
| The Yeehats | A fierce tribe of Indians who murder Thornton and his partners |
| Spitz | A white dog who is Buck's archenemy among all the other dogs |
| Curly | A Newfoundland dog who accompanies Buck on the voyage of the Narwhal |
