- iminent danger to the person means that there is a big problem associated to health or the environment where the person is sleeping. Also, it could be a problem associated with something which is included, as a model, into the PSM (close relatives, some objects or situations, some problems etc). - there is a danger, but it is not associated to the person or close relatives. - It is a neutral dream, no danger. This is a normal wake-up dream. For instance: the dream is associated with a flower. The person wants to pick that flower, but fails. This situation activates the PSM, which activates the wake- up procedure. One problem could occur: how does the brain know that a certain dream will activate the PSM? A possible answer is that a dream will develop by simulation, on and on, up to the moment when the PSM is activated. When the wake-up occurs, the first active-ZM will be that one which activated the PSM and so, it will be remembered. There is an important feature of QER to be presented here. QER is built on the spot, because it is associated to a problem, which has to be solved very fast. Thus, QER cannot be too complex. It is easy to simulate the development on a simple model, which cannot be solved by the dream model. Example: The QER is associated with a room. If, during a dream, the person wants go outside the room, this is impossible, because the QER doesn't contain the exterior of the room. Thus, it is impossible to go outside and so the PSM is activated. 3. The nightmare dreams are associated with a general instability of the structure of models. A nightmare cannot occur in a brain which is in a normal status. A nightmare dream might try to activate the PSM, but the PSM does not activate. Even more, if the PSM activates (the nightmare becomes the active- ZM) the nightmare continues. This problem is too closely associated to the technological implementation of the brain and so it cannot be treated by the theory only. 4. We shall introduce another class of dreams: premonition dreams. There are many ZAM-type models, which work very well for a long time. But, as the person ages, some of them cannot meet the requirements due to the changes in the internal parameters of the execution organs (legs, hands etc). Such models self-activate during sleep (this is a premonitive-type dream) and find that they don't meet the requirements anymore. This result can activate the PSM too and produces the wake-up. The contents of such dreams is important but, unfortunately, it is difficult to make the difference between a wake-up dream and a premonition dream. Anyways, a premonition dream has to be taken as a serious warning. The dreams are associated with the technological implementation of the brain. MDT, as a fundamental theory, cannot go beyond a limit. What was presented here has to be considered just an evaluation of the dream problem. ETA 17: The history of evolution of the human species, based on MDT