My problem was with the books is the lack of depths of characters as the story moves forward - at the end they become mere tools to tell the impossible future.

My problem was with the books is the lack of depths of characters as the story moves forward - at the end they become mere tools to tell the impossible future. But there are astoundig amounts of fascinating ideas and theories in the books it's well worth the read - it became one of my favourite sci-fi next to Solaris. If you can, read it without any previous info - there are big spoilers in almost every description of the book.