Author Jon Krakauer attempts to describe other men of similar qualities to Chris McCandless in chapters 8 and 9 of Into the Wild.
Chapter 8 focuses on Gene Rossellini, John Waterman, and Carl McGunn. The similarities between those three men and Chris are small. Mainly those three are men that sought solitude in the Alaskan wilderness and died. That's what happened to Chris as well. While all three men bear some similarities to Chris, Krakauer admits that they were still not enough like Chris to fully understand what might have made Chris "tick."
There are similarities among Rosellini, Waterman, McCunn, and McCandless. Like Rosellini and Waterman, McCandless was a seeker and had an impractical fascination with the harsh side of nature. Like Waterman and McCunn, he displayed a staggering paucity of common sense. But unlike Waterman, McCandless wasn’t mentally ill. And unlike McCunn, he didn’t go into the bush assuming someone would automatically appear to save his bacon before he came to grief.
Krakauer tells his readers that in order to better understand Chris, he needs to inform readers about Everett Ruess.
Some insight into the tragedy of Chris McCandless can be gained by studying predecessors cut from the same exotic cloth. And in order to do that, one must look beyond Alaska, to the bald-rock canyons of southern Utah. There, in 1934, a peculiar twenty-year-old boy walked into the desert and never came out. His name was Everett Ruess.
Ruess and Chris are unbelievably similar in a variety of ways. Both men began their solitary journey as young men. Both men also didn't shy away from rough, rugged, and harsh conditions.
Also like McCandless, Ruess was undeterred by physical discomfort; at times he seemed to welcome it.
Both men had a habit of taking on aliases during their travels. Chris often told people that his name was Alex, and he had a habit of signing his stuff "Supertramp." Both men enjoyed their solitude, but both men didn't shy away from friendly companionship either. They simply didn't tolerate it for very long.
We like companionship, see, but we can’t stand to be around people for very long. So we go get ourselves lost, come back for a while, then get the hell out again. And that’s what Everett was doing.
Personality wise, Ruess and McCandless are cut from the same cloth. The only difference that I can think of, based on Krakauer's text, is not a personality difference. We know what happened to McCandless. His body was found. Ruess's body was never found.