The German Ideology, co-written with Engels in 1845, was also unpublished but this is where we see Marx beginning to develop his theory of history. The Communist Manifestois perhaps Marx's most widely read work, even if it is not the best guide to his thought. This was again jointly written with Engels and published with a great sense of excitement as Marx returned to Germany from exile to take part in the revolution of 1848. With the failure of the revolution Marx moved to London where he remained for the rest of his life. He now concentratedon the study