Fiss makes a lot of interesting points that other scholars do (would?) not about the major topics of constitutional jurisprudence of the Fuller Court. I'm not sure he really brings the title (subtitle?) of his work to the fore. What makes the "state" in that era "modern?" What were the problems of the "modern state?" Do they have a coherent and limited sets of causes? Did the Supreme Court of that era increase or decrease those problems? It's a provocative title, I think.
Still, it's thorough and good. This is probably the work for interesting conclusions about the Fuller Court.