Behind every successful business is a hidden back-end business powering it behind the scenes. No one knows this better than Jenn Hyman, CEO of Rent the Runway. RTR is known for creating a glamorous “closet in the cloud,” but it achieved ‘unicorn’ status by mastering the businesses behind their public-facing brand — including the world’s largest dry-cleaning operation and a data insights practice that’s changing the fashion industry. Cameo appearance: Kevin Venardos (Venardos Circus); Stewart Butterfield (Slack)