Das Kapital
Das Kapital (1867) is an economic treatise by Karl Marx. The book is an analysis of capitalism. Marx bases his work on that of the classical economists like Adam Smith, David Ricardo, and even Benjamin Franklin. The central injustice of capitalism, according to Marx, was that employers made their profits by paying labourers less than the true value of their labour.
Marx died before he could finish the second and third volumes, but a version of the entire work was published posthumously, edited by his friend Friedrich Engels. The work included a three-volume appendix, The Theory of Surplus Value. The first English edition of Das Kapital, Capital: A Critique of Political Economy, also edited by Engels, was published in 1887.
Marx notes in his preface to the French edition of Capital that the beginning of his work is not easy reading as he defines many terms, but once he has gotten through that it becomes easier to read. Others have subsequently agreed that the very beginning of Capital is the most difficult part to get through, which puts some people off from reading it.