Who is Quintus Mucius Scaevola from On the Good Life and what is their importance?

Quintus Mucius Scaevola was one of Cicero's teachers, as well as a member of the famous Scaevola family. He features prominently in Laelius: On Friendship and On the Orator as a member of both dialogues. He related the conversation with Laelius to Cicero, who then wrote it down.