Charles Spencer wrote Killers of the King about the long aftermath of the English Civil War, focused on the regicides, the men who signed the death warrant of Charles I in 1649. After the Restoration in 1660, the new king Charles II went looking for them, and Spencer follows the manhunt across England, Europe, and even into colonial New England.
Spencer is a popular historian, not an academic, and the book reads like good narrative nonfiction. There are character sketches of the regicides themselves, the trials of those who were caught, and the strange later lives of those who managed to flee.
The research is solid. The writing keeps moving. For readers who like Antonia Fraser’s narrative biographies or anything by Simon Schama, this is in the same neighborhood.
Not a starting point for the English Civil War overall. Better as a follow-up after a general history of the period.