Constantin Merezhkowsky is celebrated today for his theory of symbiogenesis, postulated in the early decades of the twentieth century, particularly that chloroplasts were symbiotic cyanophytes (cyanobacteria). While biologists point singularly to what they see as his heroic achievement, its neglect and subsequent rediscovery, we introduce a broader and much more complex perspective on his science, his troubled life and career. We present a view of Merezhkowsky as zoologist, anthropologist, botanist, philosopher, and novelist. We explain the genesis of his theory of (...) the origin of chloroplasts and of nucleus and cytoplasm as symbionts, as well as his depiction of the geo-chemical context of the origins and early evolution of life on earth. We also disclose his sordid social and political activities, his eugenics and racist writings, his paedophilia, and his metaphysics. Finally, we describe the context of his elaborate suicide in 1921. (shrink)