Monism as Connecting Religion and Science" explores the theory of metaphysics and theology, maintaining that there is but one reality, namely, matter, whether matter be an agglomerate of atoms, a primitive, world-forming substance or the so-called cosmic nebula out of which the world evolved. It was written by Haeckel, a German contemporary of Darwin and also a biologist, naturalist and philosopher. "Life and Matter" is a criticism of Haeckel's work, written by Sir Oliver Lodge, a renowned British physicist living between 1851 and 1940.