No modern account of the history of the Academy as a whole exists. For the early history of the Academy, the last 3 1/2 centuries BC, we are in an unusual situation, as compared with the other schools of philosophy, that two historical accounts are preserved: Papyrus Herculanensis 1021, the Index Academicorum, and Book 4 of Diogenes Laertius' Lives and Opinions of the Philosophers. Comparison of these two sources gives us a better possibility of determining what belongs to the main tradition and what is peculiar to each source.
Mejer, Jorgen, "Philosophical Lives: The Academics" (1986). The Society for Ancient Greek Philosophy Newsletter. 141.