When I was a kid, I didn't have any clue that someone actually drew Star Wars before it "happened". I had no idea what a concept artists even was. I remember seeing a painting (below) and thinking "That's not Star Wars! It's like Star Wars, but somehow 'off' a bit." How wrong I was--it was the essence of everything George Lucas was trying to achieve. It sold 20th Century Fox on his ideas, and it propelled production by serving as the blueprint for Industrial Light and Magic's efforts to bring the script to life.
But one thing was certain, his work was electrifying. And it ignited my imagination so much that for a time I was a McQuarrie junkie, hunting down his work wherever I could find it. This in turn led me to learning about filmmaking, which eventually became part of my area of study in college.
I owe a great deal to his work, in part because it was one of the earliest lessons I learned about creativity--that every idea comes from somewhere and there are a million directions every idea can take. I still look at his work and can think of a different backstory for every character, starship, or planet. That's the real power of art--to move the viewer's imagination as much as the person who created it.