On 1/13 we recorded a discussion of an early work of Karl Marx, from about 20 years before the publication of his famous Das Capital, The German Ideology. Listen to the episode. We read just part 1 of the work, which was written in 1845-6 but not published until 1932 (with some portions of it coming out earlier in the 20th century). The work is credited to Marx and Engels, but according to the editor of the version I read, it's pretty clear that the part we read was Marx's work.
The book is more philosophical than his later work, though its substance is in part an attack on philosophy, in particular that of the Young Hegelians like Bruno Bauer and Max Stirner. As you might recall from our Hegel on history episode, Hegel saw history as progressive, and analyzable in terms of "Spirit," as in the spirit or intellectual climate of the times: you can (maybe) predict what will come next historically (e.g. will this democracy become a tyranny?) by looking at the big ideas driving the times. One idea somehow leads to the next one in a "dialectical" manner, e.g. a reaction against the current state of things, in turn supplanted by a synthesis which is more like the original position but changed to incorporate some of the advances to the second position. To use a musical example, 70s prog rock leads to the punk reaction, which turns into new wave/post-punk, which is artsy like prog but keeps some of the energy and simplicity of punk.
Though Hegel himself was very clear that movements through history take place through concrete individuals, and it's not like some guiding intelligence is molding the progression, post-Hegelians were not always that cautious, and many focused on the theological aspects of it. Politically, Hegel himself got conservative in his old age (thinking that the culmination of history had already happened in the Prussian constitutional monarchy), and the Young Hegelians (or "Left Hegelians") were generally radical, often atheist at at least highly unorthodox, but still concerned with addressing Hegel's philosophy of religion (following Schleiermacher). Marx insisted that while the idea of historical dialectic was still useful, it had to be interpreted in a purely material, scientific manner, so this book is one of his earlier attempts at an Adam Smith-influenced account of how the ways in which people produce the goods they need to survive has evolved, and so (and this part is not in Smith, of course) extrapolate this picture forward to argue that communism is inevitable.
Writing at around the same time as proto-existentialists like Nietzsche and Kierkegaard, Marx also had a picture of the human condition that stressed the danger of an inauthentic, alienated relation to each other and the world. He thought that capitalism, where most workers don't own, and feel no particular connection to, the products that their work contributes to, has led to alienation, where each of us sees our jobs, i.e. what we do pretty much all day and which defines us whether we want it to our not, as nothing but a means to the end of our happiness and not as something worthwhile in itself. We end up by necessity treating each other merely as a means, dehumanized and wretched.
Unlike the existentialists, though, fixing this can't be accomplished just by shifting your attitude. The problem is not with false or unhelpful beliefs, but an economic system that objectively damages us and keeps us from being free. Even though we're not slaves, we don't have any choice but to work, and this "freedom" is a matter of being subject to the whims of chance... What if I get injured and can't work? What if I can't find a job at all? Famously, Marx thought that given that the status quo gets perpetuated by dominant interests, i.e. the capitalists fat cats themselves, and that the government and even the intellectuals (the philosophers he's so contemptuous of, and also the clergy) just serve to parrot these interests, the only way to get to the solution is violent revolution, which is inevitable, given how historical forces will steadily put us into a situation where the vast majority of us are in this alienated, wretched situation. This last, predictive part of the program, is of course highly problematic, but that doesn't lessen the force of his diagnoses of modern ills.
A very short work Marx wrote at the same time that he and Engels were starting on the German Ideology is "Theses on Feuerbach," which is just a few pages of aphorisms that serve as an outline of the themes of the Ideology. His final thesis there (number 11) sums up his overall project praxis:
The philosophers have only interpreted the world, in various ways; the point is to change it.