In its third year, "Scraphead Challenge" is one of Channel 4's most successful Sunday evening series, with a regular audience of over three million viewers. It's a knockout competition for amateur engineers - each week, two new teams of madcap mechanics have to work against the clock to build a specific machine from whatever junk they can scavenge. "Behind the Scenes at Scrapheap Challenge" looks at what goes on behind the camera as well as on screen, using six case studies from the series and scores of colour photographs. The teams have just ten hours to come up with the goods and get one step nearer to the season finale. The book follows the would-be engineers and presenters Robert Llewellyn and Cathy Rodgers' progress as the competition hots up. Through the interviews with the cast and crew, we discover what it's really like to take up the "Scrapheap Challenge".