This is a great book by Isaac Asimov, scientist and science fiction writer. Although the book is heavy at 880 pages; content is light. Isaac's enthusiasm for the subject crosses to the reader and makes for a very enjoyable read. Unfortunately as Isaac Asimov wrote in the book "Science will not stand still", written in 1984 it has dated a bit and I think it should be picked up by other scientists and updated for the new millennium. Although undeniably it is still a very good read. More people need to enjoy science and I think this book could do the job.