As we have discussed in class, death is a prominent theme in War and Peace. This is not accidental. Even as a child Tolstoy was no stranger to death, losing first his mother, then his father and his grandmother. This caused him to think a lot about death and its consequences. This is evident in many places in War and Peace, especially on page 123 when Nicholas first rides into battle and in Book Four, Chapter 9 when Lise dies. Tolstoy saw death as a common and unavoidable theme of life, thus it comes up frequently in his writing.
Tolstoy himself shares many similarities with his characters as well. As a youth he struggled with a gambling problem, which is reflected in many places in the novel including Book Four, Chapter 13 when Nicholas gambles with Dolokhov and loses. However, the character Tolstoy is most similar to is Pierre. The description of Pierre as a bear, and as being large and awkward is very similar to how Tolstoy saw himself. Furthermore, Tolstoy and Pierre share a weakness: women. Similar to Pierre's situation in War and Peace, Tolstoy slept with many women in his youth, which conflicted with his morals. Finally, in 1856 Tolstoy tries to free his serfs, just as Pierre does in the novel. However, neither attempt was very successful.
One of the reasons War and Peace is so successful is that it deals with many universal human problems, such as the struggle with death, religion, and addictions like gambling and women. In many ways it is Tolstoy's own experiences that form the heart of the novel.