There is enough evidence to begin making strategic sense of cyber warfare, but a considered approach must be taken to identify the strategic implications of cyber warfare to date. This chapter reviews the current state of strategic thinking on cyber warfare, and explores why there is a lack of strategic understanding on the subject. It analyses three primary case studies in order to draw out the implications substantiated by the practical application of cyber warfare. The cases considered are the cyber-attacks against Estonia in 2007, against Georgia in 2008, and the use of the Stuxnet virus against the Iranian nuclear programme in 2010. Despite the uncertainty that pervades the present understanding of cyber warfare, there are three strategic certainties that can guide thinking moving ahead: cyber warfare will grow in strategic significance; cyber warfare will not be a strategically decisive instrument; and cyber warfare will remain strategically ambiguous.