I use this book in my undergraduate course on Marx because it so vividly illustrates the living conditions of the English working class in the 1840s. It appeared the same year (1848) as Marx and Engels' Communist Manifesto. Although Gaskell's politics are quite different - she believed reconciliation between the classes was possible and desireable whereas Marx did not - her book nevertheless illustrates many of the characterizations of capitalism in such theoretical texts as Marx's Capital in a very human way. The website for that course - http://www.eco.utexas.edu/facstaff/Cleaver/357k.html - contains some links to other, related, materials, as well as some powerpoint slides for my lecture on the book and its relationship to Marx's critique of capitalism.