弗裏德裏希·恩格斯/Friederich Engels
弗裏德裏希·恩格斯（1820—1895），馬克思主義創始人之一，馬克思的親密戰友。恩格斯出生於德國紡織主家庭，與馬克思相識後並肩戰鬥，共同起草《共產黨宣言》並領導第一國際工作。著有《反杜林論》等大量著作。馬克思逝世後，他擔任整理和發表馬克思的文獻遺產和繼續領導國際工人運動的重任，參加創建並指導第二國際工作，同各種機會主義進行了堅決的鬥爭，直至1895年8月5日病逝。
On the 14th of March, at a quarter to three in the afternoon, the greatest living thinker ceased to think. He had been left alone for scarcely two minutes, and when we came back we found him in his armchair, peacefully gone to sleep—but forever.
An immeasurable loss has been sustained both by the militant proletariat of Europe and America, and by historical science, in the death of this man. The gap that has been left by the departure of this mighty spirit will soon enough make itself felt.
Just as Darwin discovered the law of development of organic nature, so Marx discovered the law of development of human history: the simple fact, hitherto concealed by an overgrowth of ideology, that mankind must first of all eat, drink, have shelter and clothing, before it can pursue politics, science, art, religion, etc; that therefore the production of the immediate material means of subsistence and consequently the degree of economic development attained by a given people or during a given epoch form the foundation upon which the state institutions, the legal conceptions, art, and even the ideas on religion, of the people concerned have been evolved, and in the light of which they must, therefore, be explained, instead of vice versa, as had hitherto been the case.
But that is not all. Marx also discovered the special law of motion governing the present-day capitalist mode of production and the bourgeois society that this mode of production has created. The discovery of surplus value suddenly threw light on the problem, in trying to solve which all previous investigations, of both bourgeois economists and socialist critics, had been groping in the dark.