Speaking of Marx's biography, you may also consider Isiah Berlin's Karl Marx:
Berlin, Isaiah (1963) Karl Marx: His Life and
Environment, New York: Time Incorporated.
Also, Ferdinand Toennies has a very interesting biography:
Tönnies, Ferdinand (1921). Karl Marx: His Life
and Teachings, translated by. C. Loomis and I.
Paulus, Michigan State University Press.
Best,
Huseyin Ozel