People today often communicate instantaneously across vast distances and cultures: students in Ohio take online classes at MIT, and tweets from Tehran find readers in Atlanta. You will almost certainly find yourself writing to (or with) others throughout the country and across the globe, and students in your classes may well come from many countries and cultures. When the whole world can be your potential audience, it’s time to step back and think about how to communicate as effectively as possible with a diverse group—how to become a world writer.