The Age of Innocence by Edith Wharton
The cover pictured here is particularly apropos because, to us, Edith Wharton's words are like perfectly aimed arrows that never miss their marks (our dumb, old hearts). This woman couldn't write a bad sentence if her life depended on it. All of her books are worth a read, but Gatsby lovers might get a particular kick out of The Age of Innocence: both books satirize the strict class structure of Jazz Age New York while also telling the heartrending story of lovers hoping to re-spark an old flame. Be warned: you will throw this book across the room at least once because it is just too good.