Chapter 10 talks a lot about externalities and how they affect other people.  Externalities exist in both negative and positive aspects.  However no matter if the externality is positive or negative it causes the market to allocate its resources and eventually it becomes inefficient, which is not good for a market.  There is also a debate as to what the Government should do in terms of externalities.  Governments try to step in by imposing taxes and subsidies in order to get rid of these externalities.  There is also the idea that people should step up for themselves and try to solve the problems of externalities without the governments help.  This is called the Coase theorem, it is similar to where people should pay a tip instead of paying a tax in order to get rid of taxes.  There is also the time where private parties can step in by themselves and try to fix the issue.  This is fine if there is a free market where everyone has the ability to benefit.