In The Great Gatsby, as is the same in any story, the setting is important because it helps set the tone (the author's attitude) and the mood (the reader's feelings) of the story. It also gives you a visual of a time one is not familiar with since it is set several years ago. The setting is also important to appeal to imagery (or all of your senses). Without the setting, one cannot place characters accurately or understand the actions of characters if they do not know the appropriate time, place, etc.