Interesting. I first read ZAMM first when I was 15, and really enjoyed it, but I would strongly encourage everyone who has not read "Lila" to please read it, as Pirsig basically retracts most of what he said in ZAMM. In his own words, "Lila" is his "smart child", and the book he wants to be remembered by. It is a much better book than ZAMM.

If anyone is interested, I just discovered William James Sidis's "The Animate And The Inanimate" here:

http://www.sidis.net/ANIMContents.htm