Does an author have a say in the cover of the book? I always assumed that it was designed by the author, but then, I read a while back that it's all up to the editor and illustrators etc. Is this true? You just write the story and have no say in the format, cover, illustrations, etc..?
Usually it's up to the editor and/or the art department. The author may sometimes be consulted about elements of the cover at those people's discretion, but it's not usually up to us. The one Trek novel cover I had the most input into was for Titan: Over a Torrent Sea
, since it was based on my descriptions of Aili Lavena's appearance, and I was allowed to offer notes on the draft cover and suggest some refinements to the details. I was asked to suggest a cover idea for DTI: Watching the Clock
, and there was a draft cover that was loosely based on my suggestion, but it didn't ultimately work and the final cover just used one element of my suggestion (the use of the Shepherd Gate Clock from the Greenwich Observatory).
The one case where I made a suggestion up front and it ended up being used was on the Only Superhuman
cover. I sent my editor (Greg Cox) some sketches I'd done of the lead character, and though he warned me not to expect the art department to use my design for her, their artist actually followed it remarkably closely, allowing for a bit of poetic license -- though the actual pose, setting, and situation she's in on the cover were the artist's decision.