Complex sentence: Edson and Sandburg wrote frequently to each other for about five years, sharing an enthusiasm for the philosophy of Elbert Hubbard, the poetry of Walt Whitman, and the dream of a socialist paradise.
Split into simpler sentences: Edson and Sandburg wrote frequently to each other for about five years. They shared an enthusiasm for the philosophy of Elbert Hubbard, the poetry of Walt Whitman, and the dream of a socialist paradise.