My impression as a science or a technology it takes only the legitimate economy (that is under the rule of Law) as its proper sphere.
That there is a preponderance of studies on the legitimate economy may be simply due to its greater visibility, its obvious legitimacy, the enormous mass of data associated with it.
But it seems to me that the illegitimate economy has an equal right to be called an economy. It has its own Law immanent in itself.
Are there any studies that say how these two economic substances actually interact? Where one substance flows into the other (by seeking a weak point to puncture by violence or cunning)? Then is there then only one actual economic substance?