Frank: Arundel was, IIRC, Robert's first novel. It is one of three that comprise what is called "the Arundel Chronicles" (the other two are Captain Caution and The Lively Lady). Arundel is many things - my favorite Roberts' book for one - adventure story, political story, a story of unrequited and requited love, of strategy and revenge in a war from an age gone by.
In brief, the tale revolves around Benedict Arnold's gathering a force in Arundel, Maine and their doomed march up the Kennebec River to attack Quebec. Great stuff.
Phoebe Marvin - one of the great females in modern lit.
One reviewer said it this way:
5.0 out of 5 stars Pinnacle of American Historical Fiction
ARUNDEL is quite simply the finest historical novel that I have ever read.
It is also one of the finest works of American fiction, period.