Lloyd P. Gerson's work on Platonism -- defining what it is, and describing how it was contributed to and developed in antiquity -- is of inestimable value. "Aristotle and Other Platonists" is the first (2005) of three related volumes published by Cornell University Press, the succeeding ones being "From Plato to Platonism" (2013), and "Platonism and Naturalism: The Possibility of Philosophy" (2020). And of those writings of Gerson's that I have read, these touch on many of the same subjects: "Plotinus" (London: Routledge, 1994), and "Knowing Persons: A Study in Plato" (New York: Oxford University Press, 2003).
The three basic contributions of Gerson, to be used in guiding our interpretation of the Platonist tradition, including in the first place the works of Plato, Aristotle, and Plotinus, are these: 1. the common core of Platonism is a set of related views opposing certain philosophical stances that are rejected, viz. antimaterialism, antimechanism, antinominalism, antirelativism, and antiskepticism; 2. Aristotle, who is correctly understood to share these views, is indeed a most valuable witness to Plato's thought; 3. what has looked to philosophical historians like doctrinal weakness, incoherence or untenability among the various contributors to the Platonist tradition is usually to be ascribed to the underdetermining quality of the core Platonic values, which allows for a good bit of freedom in the development by particular writers of particular dogmas.
Gerson's reformation of our conventional reading of Aristotle with regard to Plato is a task of fundamental importance that necessarily begins his project. Aristotle criticizes Plato and his school at many places, and indicates where he must part company with them. (Cf. the notorious adage, "Amicus Plato, magis amica Veritas," "Plato is a friend, but Truth is even more a friend," based on a comment about Plato's superordinate Good and the Theory of the Forms in the Nicomachean Ethics I.vi.1, 1096a15.) Modern interpreters have tended to interpret these differences as signs of a radical new direction for Aristotle, even an explicit opposition to Plato. Gerson instead argues that the interpretation of Plotinus and other Neoplatonists is much preferable: they have no problem accepting Aristotle as a fellow Platonist, often use his more elaborate doctrines to express ideas that in Plato himself are not quite developed to their satisfaction, and show his criticisms to be the result of misunderstanding.
The quality of these three volumes as works of scholarship is outstanding, and Cornell UP is to commended for allowing Gerson to provide in footnotes the Greek texts of the ancient lines he quotes and cites in English, and also a full index of the passages he cites from the numerous works by ancient authors, as well as an appendix of names of Platonists and Aristotelians, a lengthy double bibliography (ancient and modern), and an index of topics. The project that this trilogy carries out should not only reform and redirect historians' interpretations of these ancient philosophers, but might even foster the development of a Platonist revival, the cultivation of a reborn way of life of remarkable beauty.