Strauss, Leo, "Plato," History of Political Philosophy, 3rd edition, eds. Leo Strauss and Joseph Cropsey, Chicago, IL: University of Chicago Press, 1987.

Excerpt:

Thirty-five dialogues and thirteen letters have come down to us as Platonic writings, not all of which are now regarded as genuine. Some scholars go so far as to doubt that any of the letters is genuine. In order not to encumber our presentation with polemics, we shall disregard the letters altogether. We must then say that Plato never speaks to us in his own name, for in his dialogues only his characters speak.

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