A Close Look at America is a popular book introducing American legal and administrative life, which is very interesting.
If you want to read professional books, you can read:
On the spirit of law, Montesquieu, a professional book, is easier to read.
Crime and Punishment, Beccaria, a classic.
He Fan's Translation of Criticizing Officials and Upholding Justice-Notes on American Judicial Observation.
Rawls' Theory of Justice and Aristotle's Politics are also good.