With the recent resurgence of interest in socialism on the American left, it's worth revisiting John Stuart Mill's Chapters on Socialism as probably one of the best attempts ever to think through systematically both the merits of the socialist critique of capitalist society and the viability of its proposed alternatives.
Better than perhaps any writer in history on the topic, Mill performs the feat of holding multiple ideas in mind at the same time—and managing to distinguish between them. He is therefore the opposite of that individual William Hazlitt once identified as the great pest of all political life: "the person with one idea."