Lol what??? Marx is either gonna be number one, or the list is assuming you’ve already read the manifesto. Capital should absolutely be in the top 80, and the only reason it isn’t usually top 10 is because anglos are too lazy/illiterate/overworked to attempt it. But many lists will have Wage Labor and Capital as well as Value, Price, and Profit as easier alternatives to Capital. Most of his stuff is essay-length and wouldn’t necessarily show up on a book list. But Essays on Feueurbach, the German Ideology, and Critique of the Gotha program are commonly recommended, for example.