After a general introduction about strategic management principles, allowing the distinction between strategic and operational management, we study the different methods and tools to perform a strategic diagnostic, both internally and externally. This leads us to a global vision of the firm position, in particular using portfolio matrices. On this basis, we look at different strategic options, first at the level of strategic business units, then at the corporate level. For all those strategic options, we consider the most relevant organisational structure and working. Finally, we study the impact of various leadership modes on strategic efficiency.