Think of the two islands as you would a set of twins. Outwardly, we look alike, but beneath the surface… we are individuals.
-- Narrator (Nantucket)

Importance: The author uses an analogy to compare the islands of Nantucket and Martha’s Vineyard to Harper and Tabitha. Even though they may look alike and have a good deal in common, they are individuals.

Six weeks earlier, when Billy got really bad, Harper copied Tabitha’s cell number out of Billy’s contacts and, with the help of half a dozen Amity Island ales and three shots of Jägermeister, left Tabitha a voice mail informing her that if she wanted to see Billy one last time before he died, she had better do it soon.
-- Narrator (Martha’s Vineyard: Harper)

Importance: Even though Harper had left Tabitha a message telling her that Billy was sick and close to dying, Tabitha had not come to visit. Now that Billy has died, Harper...