Gone Girl, the 2012 novel by Gillian Flynn is not part of a series of books, it was a one-off novel. Flynn has published two other books, Sharp Objects and Dark Places, but the story and characters of Gone Girl are not related to either of these books.
Although she currently has no plans for a sequel, Flynn has revealed that she is constantly asked if there might be one in the future. Her answer to this is that it would be fun to revisit the story and the characters, but for the time being she needs to take a little break from them. So watch this space!
Gone Girl has been Flynn's most successful novel so far. It was been received with critical and popular acclaim, so much so that a recent film adaptation was released in October 2014, directed by David Fincher.