Does anybody have any information about the seven gates of dreaming as per Castenada?

I found a wiki article about it here: http://en.wikipedia.org/wiki/The_Art_of_Dreaming

It seems very esoteric, but I thought I would ask and see if anyone has any experiences with these gates. Some say that Castenada is for real while others believe that all of his books are fiction. However, could passing these gates be beneficial for the majority of lucid dreamers?