 "Off the Main Sequence", published in 2005, includes three short stories never before collected in any Heinlein book (Heinlein called them "stinkeroos").Spider Robinson, a colleague, friend, and admirer of Heinlein, wrote "Variable Star", based on an outline and notes for a juvenile novel that Heinlein prepared in 1955.The novel was published as a collaboration, with Heinlein's name above Robinson's on the cover, in 2006.