One of the most important achievements in astrophysics during the period 1968-1970 was the realization that in addition to ``ordinary'' stars which derive their energy from nuclear reactions, there are objects in the Universe whose radiation is caused by a strong gravitational and magnetic field.
Well-known examples are neutron stars and white dwarfs. Less studied examples are magnetic stars, and more hypothetical are supermassive rotating stars, spinars, which might be responsible for galactic nuclei and quasar activity (see Lipunov, 1987).
The property that these objects have in common is that their astrophysical manifestations are determined by interaction with the surrounding matter. This interaction is provided by two kinds of physical forces, gravitational and electromagnetic. The importance of this fact was initally understood for NS (Schwartzman 1970a, 1971[173, 176]). In the early 1980s, this approach led to the creation of a complete classification scheme involving various regimes of interaction between neutron stars and their environment, as well as to the first Monte Carlo simulation of the NS evolution (see Lipunov, 1984). Apart from NS, this scheme has been shown to be applicable to other kinds of stars.
By virtue of the relationship between the gravitational and electromagnetic forces, the NS in various states can manifest itself quite differently from the astronomical point of view. Accordingly, this leads to the corresponding classification of NS types and to the idea of NS evolution as a gradual changing of regimes of interaction with the environment. The nature of the NS itself turns out to be important also when constructing the classification scheme. This indicates that there should be a whole class of quite different objects which have an identical physical nature. To develop the theory describing properties of such objects (in a sense, it should establish ``ecological'' links between different objects), it seems convenient to use symbolic notations elaborated for the particular case of NS. We start Section 4 with recollecting the magnetic rotator formlaism (mainly according to the paper by Lipunov (1987)) and add some new general results.