What Is Foucault's 'Discipline And Punish'?

Michel Foucault presents a challenging read in the book, Discipline and Punish: The Birth of the Prison. Foucault explains how punishment has changed over time from a corporal, physical punishment to a punishment that is targeted at souls. Foucault walks the reader though how the disciplinary and penal system has changed as the body was discovered as an object and target of power. Foucault begins this book by recounting the fate of a man called Damien the regicide, who attempted to assassinate King Louis XV of France in 1757. He was publicly tortured for hours, beaten, stabbed, crushed and eventually quartered by horses. Foucault says that public executions and scenes like this were common and happened every once in a while for those who were accused of heinous crimes. This practice, inhuman and brutish, was recognized as a legal form of punishment just two centuries ago. Criminals were subjected to torture, flogging, beating, humiliation
For most of the reading, I was not entirely sure what Foucault was getting at. Foucault dropped hints here and there but more importantly, he intends to allow the reader to see for themselves. Foucault attempts to make the reader understand the relation between power, culture, and the individual.
Foucault tells us the modern prison system is the model for control in society. What happens behind the prison walls becomes so distant to the people outside the prison, that they have no empathy for the people who suffers in solitary confinement or sleeps on cold prison floors. The sufferings become none of the publics’ concern. There is a dehumanizing effect that the modern prison has on the criminal, an effect that expels any chance of sympathy or pity for the prisoner. Foucault shows this was not the case back when people were tortured in streets and executed