In Marxism, a theoretician is an individual who observes and writes about the condition or dynamics of society, history, or economics, making use of the main principles of Marxian socialism in the analysis.

The Poverty of Philosophy is a book by Karl Marx published in Paris and Brussels in 1847, where he lived in exile from 1843 until 1849. It was originally written in French as a critique of the economic and philosophical arguments of French anarchist Pierre-Joseph Proudhon set forth in his 1846 book The System of Economic Contradictions, or The Philosophy of Poverty.