This book is a biography of Engels, one of the founders of Marxism and known as the great "second fiddler." Engels's life is inseparable from Marx's theoretical research and practical activities. As Marx's closest and most trusted partner, no one can replace Engels' historical role in the birth, development, and dissemination of Marxism, as well as the world proletarian revolution and the international communist movement. Marx's decades of academic and revolutionary career would not have been possible without Engels' selfless help. Together they study philosophical issues, fight against enemies together, and guide the way forward for the world's proletariat. The book highlights Engels' lifelong revolutionary ideal of fighting for the "liberation of the working class." After Marx's death, Engels was called "the most outstanding scholar and teacher of the modern proletariat." His brilliance was, to a certain extent, no less brilliant than Marx's. The author is an expert on the history of Marxism and the history of the world communist movement who once worked for the Central Compilation and Translation Bureau. In the process of creation, he not only absorbed excellent research results at home and abroad, but also incorporated his own years of research experience. The book has fluent language, rich content, pictures and texts, and is fascinating.