I was introduced to both Dennett and Lem through 'The Mind's I: Fantasies And Reflections On Self & Soul', an anthology edited by Hofstadter and Dennett that I chanced upon in the university library. I recognized Hofstadter from GEB. I found 'I' very digestible, I admit that I still haven't finished GEB. It beckons me from the bookshelf.
Every generation or so a book comes along that, in retrospect, seems almost clairvoyant. This is one of those books.