I le 1848, na tusia ai e Engels le Communist Manifesto faatasi ma Marx ma tusia ai foi ma tusia faatasi (aemaise lava ma Marx) le tele o isi galuega. Mulimuli ane, na lagolagoina e Engels Marx i mea tau tupe, ma faatagaina ai o ia e faia ni suʻesuʻega ma tusia Das Kapital. Ina ua mavae le maliu o Marx, na faasaʻoina e Engels le tusi lona lua ma le lona tolu o Das Kapital. E le gata i lea, na faatulagaina e Engels faamatalaga a Marx i luga o Theories of Surplus Value, lea na ia lolomiina mulimuli ane o le "tolu" o le Capital. I le 1884, na ia lolomiina ai le Origin of the Family, Private Property and the State i luga o le faavae o le Marx's ethnographic Question.
O Engels