David Nelken is a person who knows a lot about the law. He studies why people follow the law and what happens when they break it. He also looks at how different countries have different laws and how those laws affect people differently.
Think of it like this: You know how your teacher has rules in the classroom that everyone has to follow, like raising your hand before speaking? David Nelken studies why people follow those rules and what happens if you don't follow them.
He also looks at big rules that affect everyone in a country, like driving laws. For example, in some countries, you have to drive on the left side of the road instead of the right like we do in the US. David Nelken wants to understand why there are different rules like this and how they affect people's lives.
Overall, David Nelken is like a superhero who uses his brain to understand how the law works and why it's important.