HarperCollins is proud to present its new range of best-loved, essential classics. 'We're their slaves as long as we can work; we pile up their fortunes with the sweat of our brows, and yet we are to live as separate as if we were in two worlds...' Based in the industrial unrest of 1840s Manchester, Mary Barton is a factory-worker's daughter living a working-class life in Victorian England. She…