Op-ed by Gregg Mitman: Firms build worlds. On this, historians and businesspeople agree. Corporations have always been among the greatest forces shaping American life. And the many corporations that hold private archives documenting their past activities have unique powers to disclose—or hide—their contributions to racial injustice in America. That’s why, if they truly want to advance the cause of social justice, companies should throw open their archives for researchers to use.