Frequently much relevant knowledge about the possible future of an organisation is available. Scenario-processes are helpful with merging this knowledge, finding a common language, thus establishing a platform for communication beyond the result. On the other hand, scenarios cannot really predict the future. Scenarios are models of thinking with which we are able to approach future challenges and chances. Scenarios are “good” as long as they stimulate correct decisions. Scenarios are no actual descriptions of the future, neither. On the contrary, they are always group-subjective images of the future, i.e. they represent the points of view of those who have developed the scenarios. Additionally, scenarios are no strategies or decisions; they are thinking-tools for supporting decisions and developing sustainable strategies. One obstacle for developing and introducing scenario-based processes of strategy-development is the fact that they are very time-consuming, labour-intensive and expensive. Most enterprise and organisation cultures are focussed on quantitative prognoses or implicitly existing or supposed conceptions of the future. Very often decision-makers look at the mostly quantitative information of scenarios only as a dreamy vision (or “invented stories about the future”), which cannot be used for concrete strategic planning because of their insufficient accuracy. When working on the basis of alternatively possible images of the future, the decision-makers have to understand the future and the decision-making process as a choice from several alternatives. This kind of thinking in alternatives, however, usually is new and unfamiliar. In an organisation, the concept of “thinking in scenarios” makes a significant change of the enterprise culture necessary, and thus it also affects normative management which is also often considered to be a part of enterprise culture. Thus, enterprise culture must develop in a way which makes it possible for forward-looking thinking and thinking in alternatives and options to become natural whenever a decision is to be taken. At the same time, creative and open-minded reflection on external and internal future must be allowed and encouraged. In recent years the concept of „reasoning in scenarios“ has turned up as the central methodical instrument for analysing long-term security-political developments and foreseeing - if not predicting - appropriate fundamentals for developing security-political instruments. Here one must point out, however, that scenarios are not supposed to predict the future, which is also stated by J. H. Schoemaker in his book „Profiting from Uncertainty“. Schoemaker emphasizes that reasoning in scenarios must not be considered mainly as an “innovative planning instrument”. He holds the opinion that working with and reasoning in scenarios ought to change the instincts and attitudes of decision-makers. Scenarios are to challenge the mental models we all hold on to.