Judge Miller was Buck’s first owner.  He lived in a big house in Santa Clara Valley, California.  Buck,

“….ruled the estate. Here he was born, and here he had lived the four years of his life" (London 6).

The judge had house dogs and kennel dogs, but Buck ran the whole place. 

“...[Buck] was king, -- king over all creeping, crawling, flying things of Judge Miller's place, humans included" (London 6).

Buck was very close to the family.  He would swim and hunt with the boys, take long walks with the girls, and keep the Judge company by the library fire.

The gold rush in Alaska had increased the demand for large dogs capable of pulling dog sleds. Buck was a large dog, one hundred and forty pounds, and he would make an excellent sled dog.  The Judge’s greedy gardener, Manuel,  recognized that fact and decided to kidnap the dog and sell him.

The day Buck disappeared, the Judge was at a meeting, and the boys were at a club. Manuel took Buck out for an evening walk. He took Buck to a train station where he met a man who paid him $100 for the dog. After a train ride, Buck was taken to a small saloon. His brass collar was cut off. Without that collar, no one would know that he belonged to the Judge. That night, when the shed door rattled, Buck would expect to see the faces of either the Judge or the boys, but no one came to his rescue.  He would never see the Judge again.

What was Buck's personality with Judge Miller in The Call of the Wild?

Buck was supremely confident when he lived with Judge Miller. He felt that he ruled over the entire estate as he was privileged to go where he liked and do what he wanted. He was well fed, well taken care of, and felt an ownership over the entire place.

He felt superior to the other dogs on the place as he was bigger and more intimately connected with the humans who lived there. The other dogs "lived obscurely in the recesses" of the house but Buck lay at the Judge's feet, bathed with his sons, went hunting with them, and watched over them when they went on their "wild adventures."

He was so confident that London wrote that he was "even a trifle egotistical" as he had become like a "sated aristocrat" since his birth four years before.