A good very short introduction to Marx... Precisely as the title and author would lead you to expect.
About the book
"Peter Singer has succeeded in identifying the central vision that unifies Marx's thought. He thus makes it possible, in remarkably few pages, for us to grasp Marx's views as a whole, rather than as an economist or a social scientist. He explains alienation, historical materialism, the economic theory of Capital, and Marx's ideas of communism, in plain English, and concludes with an assessment of Marx's legacy."--Jacket.
Marx by Peter Singer, and books like it