Into The Wild (1996)
by Jon Krakauer (1954-)
This is really two narratives about a single mystery: the death by starvation of Chris McCandless in the Alaskan wilderness. The first narrative is how McCandless came to die. The second is about Krakauer’s efforts to discover the first, and to understand the state of mind that drove McCandless.
To discover McCandless’s beliefs and desires no doubt required a sympathetic state of mind to begin with, so there is naturally a lot of Jon Krakauer in the story as well. Some might find this intrusive, but the book is well written and, I imagine, well edited.