what did you learn about Chris's childhood, home life etc? does this story make us more or less sympathetic to him?

I don't think Chris had a particularly bad childhood. His father was having an affair but there was nothing to motivate Chris to abandon the world. Check this out,

http://www.gradesaver.com/into-the-wild/q-and-a/describe-what-life-was-like-for-chris-mccandless-as-he-was-growing-up-with-his-family-what-kind-of-childhood-did-he-have-what-kind-of-relationship-did-he-have-with-his-family-members-with-his-friends-79899/

@Aslan i think he did!! like in the movie! his parents kept fighting and kept planning his future he got sick of it and went to collage for a little then went into the wilderness in Alaska.

His parents did fight but in the book it is downplayed. Certainly there was tension in the family but there are tensions in most families. I don't think his childhood was abusive or so dysfunctional to cause him to give up on society and starve to death in Alaska. Chris seems a little more complex than that.