What does Buck's relationship with John Thornton signify?

Buck's relationship with John Thornton is characterized by a deep bond and mutual respect, which signifies a key theme in "The Call of the Wild." This relationship represents a transformative experience for Buck, moving beyond the mere existence he had under previous owners to finding a true companion in Thornton.

With Thornton, Buck experiences genuine affection and loyalty, which are mutual rather than one-sided. This is a significant shift from his earlier relationships with humans, where he faced brutality and exploitation. Thornton shows understanding and respect for Buck's spirit and instincts, allowing Buck to thrive and connect with his primal nature. Their relationship epitomizes a harmonious coexistence between man and dog, where love and respect flourish, highlighting an ideal bond that transcends the typical master-servant dynamic prevalent earlier in Buck’s life.

Through this connection, Buck is not only able to fulfill his instinctual needs but also finds a profound sense of purpose and belonging, elevating his character arc in the story.