A short book on a heavy topic: the history of how the "Old Court" method of constitutional interpretation gave way to the Progressive interpretation. Epstein's not a fan.
It's important because, as a result of this shift, all levels of government got lots bigger and more powerful in the ways they could legitimately regulate, subsidize, and expropriate previously private economic decisions and resources.
To get the full use of the book, it would almost certainly help to have had a recent course in Constitutional Law under one's belt. Or at least keep Wikipedia handy so that when Epstein starts talking about the Dormant Commerce Clause, you'll be able to quickly dope out what that means.
Things loosen up a bit in the final chapter which comments on cases that even a legal dilettante like your humble blogger is acquainted with: the medical marijuana case, Gonzales v. Raich and the eminent domain ruling in Kelo v. City of New London. (But even here, Epstein drags in a third case, the more obscure Lingle v. Chevron U.S.A, which ruled in favor of a rent cap on oil companies leasing gas stations in Hawaii.)
It's particularly interesting to read Epstein's take on Kelo since he became well known back in the 1980s for his book Takings: Private Property and the Power of Eminent Domain. So much so, in fact, that then-Senator Joe Biden waved around a copy at the confirmation hearings of Clarence Thomas, as a particular dangerous "natural rights" legal philosophy.
A depressing story for anyone who likes limited government, and quick fixes are, of course, unlikely. (Something similar to what happened to the Supreme Court during the New Deal, maybe? I wouldn't bet on it.)