You’re forgetting the postface to the fourth German edition of Capital. You can be forgiven because Engels refused to have it printed:

The French publisher asked to divide this work into a series, so that it be easier for the working class to read. I told them what I will now tell you: knowing the eagerness of the German working class, they will not be satisfied if they have to wait for the next instalment; they will want to rush to the final chapter to learn how we plan to create a giant communal toothbrush, following the production of other comically giant household items.