This is a top-notch survey on the development of legislation and jurisprudence on corruption in America. I assume some law schools are using this as a text in whole or in part in connection with constitutional law classes. That said, you don't have to be a lawyer to appreciate this book, as Teachout writes accessibly and economically.
While the book was written in 2014 in the wake of Citizens United and McCutcheon, one can imagine an addendum will be written to include the current administration at some point. As numerous emoluments clause lawsuits are filed against Trump, including one in which the author is involved, this book feels particularly relevant today.