The best place to look for the answer to this question with textual evidence is in the "Author's Note" found before chapter 1 begins. This section begins with a brief paragraph that announces the body of a young man was discovered by moose hunters in the wilderness north of Mt. McKinley. Krakauer then tells readers that his editor from Outside magazine asked him to write a feature article on the mysterious person.
Shortly after the discovery of the corpse, I was asked by the editor of Outside magazine to report on the puzzling circumstances of the boy’s death.
The January 1993 article wound up being a 9,000 word article, but Krakauer admits that he couldn't shake the desire to find out more about McCandless, even after having written the lengthy article. Krakauer felt compelled to retrace McCandless's final year or so of life.
Unwilling to let McCandless go, I...
(The entire section contains 2 answers and 437 words.)