CALL OF THE WILD is written by JACK LONDON.
IN SIMPLE WORDS it's a story of struggle between civilized and wild.
JACK LONDON also points some major theme,i.e-
Survival of the Fittest-Jack London believed in Herbert Spencer's theory of "survival of the fittest," which means basically that an organism or group that is better suited to an environment will have a better chance for survival than an animal or group that is less suited.
Companionship-Buck is never alone in the novel, but instead travels between a various number of humans and other dogs, often wondering why he is not completely happy.
The joy of labor-The most important idea imbued in The Call of the Wild is that everyone is suited to a particular kind of work, and everyone will be happiest if they are doing that work.
The Virtue of Humanity-Throughout the novel London questions the idea of humanity as a virtue.
The power of Instinct-