Zuckert, Catherine H., "The Trial and Death of Socrates," Plato's Philosophers: The Coherence of the Dialogues, Chicago, IL: University of Chicago Press, 2009.

Excerpt:

Alfred North Whitehead’s quip that all subsequent philosophy is merely a footnote to Plato has often been repeated, but those who repeat it do not seem to have thought much about the difference between the source and the scholarship on it. Whereas all subsequent philosophers have written treatises (even if they have also produced some more literary works), Plato wrote only dialogues.

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