Meinwald, Constance C., Plato's Parmenides, New York: Oxford University Press, 1991.

Excerpt:

Plato’s Parmenides today finds itself in a strange position: it is clearly an important work, but its import remains remarkably unclear. The difficulty of analyzing this text is due, in part, to its complicated structure. Within three frames we find the dialogue proper, itself consisting of two parts connected by a brief transitional section. The first part of the main dialogue is a series of rather brief exchanges enlivened by humor and some dramatic incident; the second part consists of almost thirty Stephanus pages of obscure and unadorned argument.

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