In Marx own writing on his method, he argues it is important to grasp the analytical and concrete moments in knowledge. The analytical moment (dividing, for example, our apprehension of the mode of production into discrete objects of analysis such as production, exchange, property, markets, social classes, law and history, etc.) is crucial. However, we then need to re-assemble the world in our imagination to grasp the concrete truth of it. This is the rational kernel of the dialectic method, as far as I can see.
Das Kapital is the perfect example of this dialectical approach to knowledge. It is history, economics, politics, sociology, and psychology all rolled into one: integrated seamlessly into a complex presentation of capital itself.