What is the author's style in The Godfather Returns by Mark Winegardner?

The Godfather Returns is separated into nine books, with a total of 32 chapters. Each book covers a particular time period, ranging from 1955 to 1962. The novel is further divided into two halves, chronologically. The first half, from 1955 -to 1958, chronicles the years between the end of The Godfather and the opening of the Godfather II. The second half takes place between 1959 and 1962, which is a period of time unaccounted for in the movie, The Godfather II. The events of The Godfather II movie take place between the first and second halves of The Godfather Returns, and the characters change dramatically.