Olly's life at home was a bigger role in the book than in the movie. The book goes more into depth on Olly's life and his person.
There is a scene in the movie where the astronaut is sitting on a bar stool in a diner that Maddy created. This scene is a reference to the famous 1942 painting "Nighthawks" by American artist Edward Hopper.
The diagrams presented during the beginning of the credits are found within the book.
When Olly and Maddy first exchange phone numbers, we can see that the last four digits of his number read 0117, which look like a numerical spelling of "Olly."
The watch Olly wears is a Casio F-91w and is now owned by a fan in New York.