Cropsey, Joseph, "Statesman," Plato's World: Man's Place in the Cosmos, Chicago, IL: University of Chicago Press, 1995, 111-44.

Excerpt:

The Stranger begins his colloquy with Young Socrates by proposing to seek out the statesman and to do so by identifying the statesman’s peculiar “science” or knowledge (episteme). If one knows what the statesman singularly knows, one knows what the statesman singularly is. Since the task is now to isolate a science, the Stranger must proceed to the division of all science, following the method he has just used in the investigation of the sophist.

Online:
Amazon