When the legendary concept artist Ralph McQuarrie died in 2012, George Lucas issued the following statement: His genial contribution, in the form of unequaled production paintings, propelled and inspired all of the cast and crew of the original Star Wars trilogy, When words could not convey my ideas, I could always point to one of Ralphs fabulous illustrations and say, Do it like this.' It's a statement that captures the essential function of the concept artist, without whom everyone from the director through to the production designers and set builders would have been unable to bring about the distinct and iconic look fans know and love. In many ways, the success of the original trilogy is thanks to McQuarrie's visionary paintings. In the decades since Star Wars the role of the concept artist has hardly diminished and is perhaps more crucial in the science fiction genre than any other kind of movie. Whether or not the film in question is based on an original idea or an adaptation or remake, the concept artist's role in bringing to life the look of the universe - from costume designs and technology to cityscapes and alien worlds - is an essential part of the final product. With complex and expensive projects often languishing in development hell, sometimes the concept art is the only window fans have into glimpsing the movie's potential. Here are 25 examples of concept art which offer a tantalizing look at 5 science fiction movies in development hell.