Landscape never is static, it always has changed, does change and will change. It therefore is not a dead object but a living process. Landscape does not only exist in three dimensions, but in four - and the fourth dimension, time, is at least as important as geographic, morphological or climatic aspects. In fact, all these aspects change in time as well, sometimes change is very slow and only to be measured in geological terms, in other cases change can be rapid. This is true for natural change, even more so for change caused by the human impact. Human beings have shaped and changed the landscape they live in, more and more dramatically so since the beginning of the Neolithic revolution about eight millennia ago. But man does not only change landscape, intentionally or unintentionally, but man also shapes the landscape in his mind and around his mind. The way people think, the things people believe in, have a crucial influence on how people treat the landscape, how they build and form the landscape. But one has also to bear in mind that landscape as such is a completely human concept. Animals live in their environment, react on their environment but they do not have a concept of landscape. As landscape is a purely human concept, the way how we perceive the landscape is an important part of this landscape. For those who deal with the landscape professionally therefore the concepts of the people living in the landscape must be one of their major features. The mental landscape, the landscape in the mind of people, as a result of the history of the landscape and the actual state of the people living in the landscape, is not only crucial for understanding the landscape and how it emerged, but as well for planning the future development, for managing the change and the process of change.