Politics and economy
Marx's first job in the book is to illustrate something which is dramatically ironic because it happens in places few people are ever allowed to see, typically speaking: He points out a connection between the government and economy which might not be obvious to people who are not political. The connection is that the government has the ability to govern the shape of businesses by imposing laws that businesses must abide by. This connection may not seem that important at first because the government should keep order in that way, but Marx illustrates how it can quickly warp the government around the will of the economy through corruption and monopoly.
The aim of the government
In a capitalist nation, the government must uphold a primary aim which is ironic considering the basic function of a government. A government only exists in the service of its people, right? This is a common mistake; in reality, the government is simultaneously overseeing people and their behavior in the citizen realm and in the business and economic realm. The government wants a healthy economy, and so in a capitalist economy, the government's agenda is to make money flow as freely in the economy as possible, making the citizens into consumers, which might not be good for them.
The invention of employment
Citizens need money to consume products, which means that there will arise a working class of people who typically rent or own a small amount of property, perhaps in a neighborhood or something. The employment of these people constitutes its own economy so that there are basically two classes of economic status: there are those who are able to own businesses, and there are those who need someone to hire them so they can trade their time for money to pay their bills and still buy the products that capitalist countries desperately want to sell them.
Advertisement and marketing
In a capitalist economy, there is an inherent risk that what is not strictly profitable will not be invested in. There is therefore a serious need for social works programs to exist, which are often incredibly difficult to start or get support for. Meanwhile, advertisers profit on those who struggle to make ends meet, because those people tend to be desperate, and through marketing products to such people, companies often convince people that their products will solve their life's problems. The problem here is how to deal with poor people, because in an economy like capitalism, those who cannot work are often out of luck.
Technology and comfort
Those who are making ends meet by working very hard in the economy of a capitalist nation are subject to another serious irony. Instead of finding ways to use their money to build money-making machines like small companies, people in the working class are enticed to spend their money at the market, which often means that they are trading their own power and freedom for technology and comfort. This might make their lives more comfort in some sense, but eventually, the schism between the wealthy and the poor will make their comfort into a kind of poisonous complacency.