This book was THE book that opened my eyes as to how to reason and think about religion when I was a JW. It opened up possibilities that I felt could be used to explain things happening in our world. Such as how religion and science could actually be explaining the same things, from different points of view.
(I mention this because it shows that reading good quality secular material can open a JW's eyes without being confrontational. Many times we want to attack the insane doctrine and policies of the WT. But for some people they need a more subtle approach.)
Anyway, I am a devoted Asimov fan. This is one of his lesser known works I think that is positively brilliant. A movie was made too of this book, though it took some liberties with the plot and, for me at least, is not as good as the book.
Isaac