The category of mood expresses the relation of nominative content of the sentence towards reality. Hence there are two moods – one presenting the action as real and the other presenting the action as unreal.
As for the imperative mood, traditionally it has been referred to as a separate mood. However, Prof. Blokh thinks that the imperative is a variety of the subjunctive.
Prof. Khlebnikova analyzed the morphological system of the English verb on the basis of oppositions. She paid proper attention to the fact that all these forms are united by one meaning – that of unreality. Since the meaning is one, but forms are different, she made the conclusion that there is only one oblique mood – Conjunctive – presented by two subtypes.
The category of mood is represented by the opposition the indicative mood vs. the spective mood. The indicative mood is the basic mood of the verb. Morphologically it is the most developed system. The spective mood, which includes the traditional imperative and the subjunctive mood, represents a process as a non-fact, i.e. as something imaginary, desirable, problematic, contrary to reality.