records impromptu comments by some famous person (made generally at the dining table or in small get-togethers), in anticipation of their lasting value.
The precedent in classical literature was the account of a symposium, such as the Table Talk (Symposiaka) of Plutarch, though this was a supposed memoir of an occasion, rather than a person.
[1][2][3] This classical genre itself derives from the more philosophical dialogues written by the followers of Socrates, and in particular the Symposia of Plato and Xenophon.
"Table talk" may also refer to a similar informal conversation, more deliberately engaged in by the famous person, with the direct intent of publication (somewhat analogous to granting an interview).
Ralph Waldo Emerson, for example, kept notes on the conversations of his family and friends, many of whom, of course, were noteworthy.