Given the seemingly endless number of iconic images that exist of Steve McQueen, it seems almost absurd to think that any photographer could be behind a collection called simply Unseen McQueen. But then, Barry Feinstein was never just an ordinary photographer.

With no formal training, the Philadelphia-born Feinstein's talent came to light in pictures taken at a racetrack where he was working in Atlantic City. Despite having quickly picked up commissions from the likes of Life and Newsweek, in 1955 Feinstein swapped the east coast for the west to take a job as a production assistant with Columbia Pictures.

Taking pictures whenever and wherever he could, Feinstein photographed many of Hollywood's famous faces (from Judy Garland to Charlton Heston). But he was drawn to more rebellious stars like Marlon Brando and Marilyn Monroe, his imagination captured by the artistic behind-the-scenes reality.

With a preference for natural light, unusual angles and stark imagery, it is little surprise that Feinstein spent much of the Sixties immersed in the music scene. Having documented several of Bob Dylan's tours, he also created hundreds of album covers for artists such as Janis Joplin and the Rolling Stones.

But it was his enduring friendship with Steve McQueen, which began in 1958, and their mutual love of bike and car racing, that defined his best work. Feinstein was always able to capture the natural intensity of the legendary movie star at his most relaxed.

Notoriously critical of his own work - he professed that he was "only interested in printing great photographs", not merely good ones - much of the material from Feinstein's collaborations with McQueen remained in his private archive until his death in 2011. Now the revealing images of the King of Cool have been put together in one stunning collection.

"I wanted my pictures to say something," Feinstein said in 2009. "I don't really like stand-up portraits; there's nothing there, no life, no feeling. I was much more interested in capturing real moments." 

To view slideshow of images, click here.