What did Henry James discuss in the prefaces to the New York Edition?

In the prefaces to the 24-volume "New York Edition" of his works, Henry James provided a significant body of commentary that combined personal reminiscence with a detailed exposition of his theories of fiction.

Following his return from a visit to the United States in 1904–05, James spent three years meticulously rewriting and revising his principal novels and tales for this collection. The 18 prefaces he composed for the edition serve as a vital record of his struggle with the problems of his craft, offering deep insight into his artistic process and his conscious approach to fictional artistry.12