There was something spare and simple about the protagonist's living arrangements in this book, that immediately qualify it for the ERE audience.
I think there's something in the book for both the artisans and rationals among us. I've read the book 3 times and found that it illuminated for me much about the hazards of self and the obstacles of other. For those of you who have read it, do you suspect that the protagonist was INTJ? (Analysis says that this book was semi-autobiographical, so I suppose the question is whether Hesse was semi-INTJ?)
One other teaser: the protagonist receives (and reads) a manuscript that recalls his present life! Aside from the narrative relief of the book within a book structure, isn't this sense similar to what happens when an ERE INTJ meets an ERE INTJ? ;-)