The general premise of the book is to take literary theory, influenced particularly by the work of Bakhtin, and she uses this to analyze Plato's creation of the discipline of philosophy. According to Nightingale (and this seems to be pretty accurate), the term philosophos (philosophy) was originally used just as the generic term for intellectuals (wisdom-lovers) and was used to describe poets, preSocratics, and sophists. Plato is the person that designated the term as its own discipline and created a specific methodology for it. It was afterward employed by Isocrates and subsequent philosophers.
I think this is a fascinating concept and plan on looking into it further. What is more important is that she claims that the evolution of the term philosophos used in Plato itself follows the pattern of the original dating of the Platonic corpus . There a significant number of problems with the original dating system, as elucidated clearly in the first chapter of Catherine Zuckert's book Plato's Philosophers: The Coherence of the Dialogues. My thesis is based partially on Zuckert's premise about the dramatic dating of the dialogues. Although I do not thing that the premise that the dialogues are written in the order originally predicted does not necessarily violate the dramatic dates, it might put something of a damper on the revolutionary aspect of the theory. I am going through the TLG results in order to determine what I think.