I've held onto this book for ten years or so but had never read it cover to cover. I can't even remember what portions of it I read when I bought it or whether I read said portions for a class or in my free time. There are sloppy margin notes I assume are mine, usually drawing forced connections between some paragraph and Foucault or Durkheim or whatever I happened to be studying at the time. Point being, as familiar as I may be with the generalities of Marxist theory and this or that specific piece of writing (some of which are not included in this book which consciously focuses mainly on Marxist political philosophy), much of this collection is either new to me or as good as new to me.
And you know what? I was missing out. It turns out that supplementing blurry memories of the Manifesto, The 18th Brumaire et al. with occasional wikipedia deep dives is no substitute for reading Marx and Engels in their own words. Even if their arguments and observations weren't so disappointingly relevant today, they offer a treasure trove of ideas and insights.
Despite the focus on the political, as opposed to the more economical or sociological, side of Marx and Engels, the scope of this book is still quite wide. It spans Marx's early, ungainly Left Hegelianism of the 1840s to Engels remarkably clear, straightforward correspondences concerning historical materialism in the 1890s. There are dense, painfully acute writings on political organization and purpose (Critique of the Gotha Program) but also lively journalistic accounts of European turmoils (The Civil War in France) and fascinating re-interpretations of historical moments and movements (The Peasant War in Germany). On the whole I find that Engels' contributions are more enjoyable -his writing style being the more fluid and concise of the two- but the book as a whole is a worthwhile read.
I'm sure there are conservatives who would find this book upsetting on every level, but I'd say this is a book for just about anyone else. One needn't be communist to recognize Marx and Engels as vital thinkers and important writers.