The sadness of finishing a book has been described as anything from an empty feeling or a book hangover, and likened to a break up and, more melodramatically, a death in the family.
You always feel a twinge of sadness when finishing a book, but it is far worse to reach the end of a book that you have loved. Author Paul Sweeney believed that the sense of loss on finishing a book was linked with the quality: "You know you've read a good book when you turn the last page and feel a little as if you have lost a friend."
One way of minimising the sense of loss is by encouraging friends and family to read the book. Then, together, you can talk about the characters as if they were mutual friends and disseminate the story as if it had really happened. It is a singular kind of happiness to obsess about a book with someone who has also found themselves lost within the very same fictional world.
Text from: HuffPost.com