Collected Works

Capital, Vol 3, subtitled The Process of Capitalist Production as a Whole, was prepared by Friedrich Engels from notes left by Marx & published in 1894. It's in seven parts:
1.The conversion of Surplus Value into Profit & the rate of Surplus Value into the rate of Profit
2.Conversion of Profit into Average Profit
3.The Law of the Tendency of the Rate of Profit to Fall
4.Conversion of Commodity Capital & Money Capital into Commercial Capital & Money-Dealing (Merchant's) Capital
5.Division of Profit Into Interest & Profit of Enterprise, Interest Bearing Capital
6.Transformation of Surplus-Profit into Ground Rent
7.Revenues & Their Sources
The work is best known today for part 3, which in summary says that as the organic fixed capital requirements of production rise as a result of advancements in production generally, the rate of profit tends to fall. This result, which orthodox Marxists believe is a principal contradictory characteristic leading to an inevitable collapse of the capitalist order, was held, as a result of various contradictions in the capitalist mode of production, result in crises whose resolution necessitates the emergence of an entirely new mode of production as the culmination of the same historical dialectic that led to the emergence of capitalism from prior forms.