Carl Sagan really brought his love of science and humanity into his first and last novel. It's a shame that he died so young. How would the world change with the knowledge that we're not alone in the Universe? Do we band together as a global species and do we let or differences annihilate us? Sagan gets very philosophical throughout the book. I feel that the heroine, Ellie, was truly Carl Sagan's voice. He sort of brings all of his ideas into one book. He also explains the science very well so me, as a lay person, can understand.
Sagan shows his weakness in fiction writing here. Sometimes the plot got bogged down by his philosophical points, but overall it was a moving story told with trepidation about our future but with a little hope thrown in at the end.
Like Sagan, I hope we as a species can learn to think globally and not annihilate ourselves so we can truly journey to the stars and make space our backyard.