Call of the Wild

I'll follow suit, Sonja. Here's some stuff about "Call of the Wild", from Wikipedia:

The Call of the Wild is a novella by American writer Jack London. The plot concerns a domesticated dog whose primordial instincts return as he works as a sled dog in the trecherous, frigid Yukon in the search of a yellow metal.
Published in 1903, The Call of the Wild is London's most read book and considered one of his best. Because the protagonist is a dog, it is often thought to be particularly suitable for children, but it is dark in tone and contains numerous scenes of cruelty and violence.

Images of death, cruelty, and Darwinian struggle abound. Of the new world Buck enters, London writes "The salient thing of this other world seemed fear."

The University of Pennsylvania's Online Books Page [1] states that "Jack London's writing was censored in several European dictatorships in the 1920s and 1930s. In 1929, Italy banned all cheap editions of his Call of the Wild, and Yugoslavia banned all his works as being 'too radical.' Some of London's works were also burned by the Nazis." (These regimes may have been reacting to Jack London's reputation as an outspoken Socialist rather than to the content of the book, which, unlike some of his other novels, has no overt political message).
In 1960, critic Maxwell Geismar called The Call of the Wild "a beautiful prose poem." Editor Franklin Walker said that it "belongs on a shelf with Walden and Huckleberry Finn". E. L. Doctorow called it "a mordant parable... his masterpiece."