Variable Star is a 2006 science fiction novel by American author Spider Robinson, based on the surviving seven pages of an eight-page 1955 novel outline by the late Robert A. Heinlein († 1988). The book is set in a divergent offshoot of Heinlein's Future History and contains many references to works by Heinlein and other authors. It describes the coming of age of a young musician who signs on to the crew of a starship as a way of escaping from a failed romance. Robinson posted a note on his website in 2009 noting that his agent had sold a trilogy of sequels based on the novel and its characters.