We have little information from external sources about the order in which Plato composed his dialogues. In the mid-nineteenth century, scholars began to study stylistic affinities among certain groups of dialogues, conjecturing that stylistically similar works were composed during the same period of Plato’s life. A consensus among scholars working independently of each other emerged, according to which the Sophist, Politicus, Philebus, Timaeus, Critias, and Laws were placed in a discrete chronological group – thought to be late, in part because we have external evidence that Laws is a late work. In recent decades, computer analysis has aided the investigation of Plato’s word choice and style. These studies can also address long-standing doubts about the authenticity of some works attributed to Plato, including his Letters. Using a variety of techniques, the Republic, Parmenides, Phaedrus, and Theaetetus can also be put into a chronological group that comes before the late dialogues but after the other dialogues. Some scholars have sought to use stylometric measures to sort the earlier dialogues, but there is not much basis for any such arrangement.