And over this great demesne Buck ruled. Here he was born, and here he had lived the four years of his life. It was true, there were other dogs . . . But Buck was neither house-dog nor kennel-dog. The whole realm was his.

When the narrator introduces Buck, readers learn that he has been living a life of comfort and ease as the treasured pet of an affluent judge in sunny California. Buck lives as a pet and doesn’t have to work for his keep other than as a companionable playmate for the judge. Buck’s life with the judge feels comfortable but limited.

Never in all his life had he been so vilely treated, and never in all his life had he been so angry.

Buck becomes outraged when his new handlers choke and pull him by a rope and brutally beat him with a rod. Living the life of a “sated aristocrat” with Judge Miller in the civilized world in no way prepared Buck for this harsh jolt of reality in the wild. Just like Mercedes, Buck’s first reaction is to take offense to the way he is treated on the frontier.

For the last time he rushed. The man struck the shrewd blow he had purposely withheld for so long, and Buck crumpled up and went down, knocked utterly senseless.

The narrator explains that Buck is beaten repeatedly by his new handlers and puts up a fierce fight as they try to “break” him in to his new role as a sled dog. Buck attacks again and again until he can’t rush the handlers anymore. Buck has learned the “law of club and fang,” which marks his initiation into his new life.

It was a token that he was harking back through his own life to the lives of his forebears; for he was a civilized dog, an unduly civilized dog, and of his own experience knew no trap and so could not of himself fear it.

The narrator reveals that Buck quickly unlearns the habits of his former life as a kept dog as he fights to make it among the sled dogs and learns what he needs to know to survive in this new life. If Buck isn’t quick enough, he will lose his food. In his former role, this would be a great offense against the feelings of fellowship that mark civilized life; here, no such fellowship exists.

He swiftly lost the fastidiousness which had characterized his old life. A dainty eater, he found that his mates, finishing first, robbed him of his unfinished ration.

The narrator describes the massive changes Buck’s body and personality undergo during his first days as a sled dog. His body toughens, his senses of sight and smell heighten, and his instincts for survival sharpen. He sheds old habits, ways of living that suited his comfortable life with the judge. The primordial beast within Buck begins to grow under the fierce conditions of life on the frontier, and his domesticated self wears away.

A certain deliberateness characterized his attitude. He was not prone to rashness and precipitate action; and in the bitter hatred between him and Spitz he betrayed no impatience, shunned all offensive acts.

At first, Buck seems content to maintain a respectful distance with Spitz: He figures if he doesn’t engage or provoke Spitz he should be fine. But the “law of club and fang” doesn’t allow disengagement: One is either in or out; one either fights for one’s life or dies. No middle ground exists. Readers later learn that Buck quickly begins to understand that he has to do more than just sit back and take the passive role.

He sprang upon Spitz with a fury that surprised them both, and Spitz particularly, for his whole experience with Buck had gone to teach him that his rival was an unusually timid dog, who managed to hold his own only because of his great weight and size.

Buck surprises himself by attacking Spitz out of the blue. As the narrator relates here, Buck surprises Spitz as well, as Buck has only demonstrated timidity up until this point. Buck is seized with a will to claim his power. He no longer feels content tolerating Spitz; he wants to usurp Spitz and gain his position as leader of the pack.

But Buck possessed a quality that made for greatness—imagination. He fought by instinct, but he could fight by the head as well.

In the chapter titled “Dominant Primordial Beast,” Buck proves himself to be the great primordial beast he was destined to be. Buck defeats Spitz, making himself the new leader of the team. As the narrator reveals, Buck’s edge over Spitz comes from his intellect. Where Spitz can only fight with a steel will and brute force, Buck can fight with imagination and cunning, two qualities that make Buck a master.

Love, genuine passionate love, was his for the first time. This he had never experienced at Judge Miller’s down in the sun-kissed Santa Clara Valley.

When Buck becomes John’s, he understands a higher octave of love than he experienced with his previous owner. With Judge Miller, Buck lived as an obedient pet, but against the backdrop of the wild, where everything exists as a matter of life and death, Buck becomes a devoted comrade with John Thornton.

The wolves swung in behind, yelping in chorus. And Buck ran with them, side by side with the wild brother, yelping as he ran.

Here, the narrator reveals that Buck’s story ends with him running alongside his newfound wild brothers: a pack of wolves. He even “yelps,” which harkens back to his time as a domesticated animal on Judge Miller’s estate. At this moment, Buck has achieved mastery as an animal that bridges the best of both civilization and primitive nature, an ideal that London expresses through the story of Buck’s life.