Cyberspace is a man-made environment created through the evolution of technology. People, institutions, organizations, and governments across the globe use cyberspace as the primary enabler for global communications, shipping, commerce, and finance. Cyberspace is also the newest warfighting domain that supports, yet challenges, traditional modes of warfare and its practitioners. Countless theorists through the centuries, such as Clausewitz, Corbett, and Sun-Tzu, have offered military theories for waging war. However, a theory for fighting from and in cyberspace has yet to be developed. Cyberspace theory would guide and enhance the DoD’s use of cyberspace in support of enterprise and military operations. For cyberspace to be truly used as a warfighting domain, it must be underpinned by theory in order to understand how to fight and win in the virtual space. Without a theoretic baseline, one will never know when to deviate from the norm and why. Evolving theories from classical theorists to create cyberspace theory will enable the DoD to effectively project cyberpower and gain the competitive advantage in cyberspace.