In the front matter of my first book, The Political Economy of Soviet Socialism: The Formative Years, 1918-1928, I chose as the epigraph a quote from Mises's Socialism that reads as follows:
It must be admitted that the idea of Socialism is at once grandiose and simple. ... We may say, in fact, that it is one of the most ambitious creations of the human spirit. The attempt to erect society on a new basis while breaking with all traditional forms of social organization, to conceive a new world plan and foresee the form which all human affairs must assume in the future --- this is so magnificiant, so daring, that it has rightly aroused the greatest admiration. If we wish to save the world from barbarism we have to refute Socialism, but we cannot thrust it carelessly aside.
I first read this quote from Mises as an undergraduate and it had a great impact on my path of study --- I even contemplated pursuing my PhD at the New School for Social Research in NYC because of it. I read everything I could on Marx for about 10 years -- original sources and secondary sources. I did this with regard to the Soviet experience as well -- as is evident from my bibliography for the above referenced book which is divided into (A) Primary and Secondary Sources on the Soviet Union, and (B) Philosophy, Politics, Economics and the History of Ideas. During this time I sought out to learn from whomever I could about Marx's body of thought. Leszek Kolakowski's The Main Currents of Marxism is indespensible for anyone on this path of study, but I would also highly recommend Andrzej Walicki's Marxism and the Leap Into the Kingdom of Freedom.
Of course, there is no substitute for reading Marx himself -- as torturous as that might be at times. The key to reading Marx is to understand his philosophical system --- namely, the methodology of dialectic materialism, and what this implies both for his critique of utopian socialists and for his analysis of capitalism. Marx's analysis of capitalism is not independent of his picture of the socialist future --- it is instead a critique from that vantage point. It is also at the core of why Marxism is not a reform agenda, but a revolutionary agenda. Both his concepts of alienation and exploitation are tied closely to his picture of a world that transcends the existing social relations of production. Justice, in short, can only be served through transcendence of the private property order of commodity production. To achieve this, Marx conceived of a rationalization project that entailed the abolition of commodity production and the establishment of a unified plan. Rationalization would produce such a burst of productivity in the economic system that the division of labor could be abandoned as we become one with our true species being.
Marx's analysis of the increasing concentration of capital, on the instability of capitalism caused by disproportionality, and the linkage between both of these and monopoly capitalism are all derived through a perspective that starts from the vantage point of a future socialist world. Socialism, to Marx, would eliminate the inherit contraditions of capitalism.
But this reading of Marx is not genuinely understood. Consider the recent discussion at the New York Times on Marx. Or this older piece by John Cassidy from the New Yorker. In these discussions, Marx's analysis of capitlaism is completely divorced from his perspective on socialism. But if the negative analysis of capitalism is only possible given his positive vision of socialism, what happens if his positive vision of socialism turns out to be faulty?
The bottom line, as Mises said, socialism is indeed one of the most ambitious creations of the human spirit, but it was also a miserable failure wherever and whenever implemented. Millions of individuals were casualties of the socialist experiments in the 20th century. It is vitally important for each new generation to understand this message --- socialism failed not because humanity failed to live up to its ideals, but because socialism fails humanity. Its problems are not bugs in the system, they are features of the system.
When I was just starting graduate school, I attended a series of lectures by Murray Rothbard that later became his history of economic thought volumes. During those memorable lectures, Rothbard stated the following which I think provides a very important guide to would-be students of the history of economic ideas. "The key to understanding the history of economic thought," Rothbard stated and then chuckled before finishing his sentence, "is to understand that Marx was a commie and Keynes was a Keynesian." He and his audience then laughed hardily. But 30 years later, Rothbard remains spot on in that advice, and in order to truly appreciate the contributions of Marx and Keynes you need to understand the full implications of that statement and once you do, you will also be able to see the fundamental flaws in both systems as well.