What is the importance of Peleliu and Okinawa in the nonfiction book, With the Old Breed, at Peleliu and Okinawa?

These two areas are the islands where Sledge and the marines engage in amphibious assault and combat operations against an entrenched Japanese enemy. Peleliu is a tiny island in what is today known as Palau; Sledge describes it as being shaped like a lobster claw. The need for the assault on Peleliu has been hotly contested since 1944. Okinawa is a small island some hundred miles south of Japan. Considered by the Japanese as part of Japan, proper, Okinawa was hotly contested and was the final major battle of World War II. Several photographs of combat action on both Peleliu and Okinawa are included in the photographic plates of the text.