Volume 26 of the Collected Works of Karl Marx and Frederick Engels contains works by Frederick Engels, most of which were written between August 1882 and December 1889.
After Marx's death Engels took upon himself the complex tasks of the development of the theory and the ideological leadership of the international socialist movement, which for many decades had been performed by himself and Marx in close collaboration. "For after all, we wish to maintain intact, in so far as it is in my power, the many threads from all over the world which spontaneously converged upon Marx's study," he wrote to August Bebel on April 30, 1883 (see present edition, Vol. 47).