Finally, an easy one. If there's anyone doing any guiding and mentoring down on Cannery Row, it's Doc. He's introduced nearly everyone on the Row to classical music and art that blows their minds:
In the laboratory the girls from Dora's heard the Plain songs and Gregorian music for the first time. Lee Chong listened while Li Po was read to him in English. Henri the painter heard for the first time the Book of the Dead and was so moved that he changed his medium. (5)
But maybe the best part is that, if you've got some kind of half-baked thought, he can present you with a gorgeous freshly-baked pie: "Doc would listen to any kind of nonsense and change it for you into a kind of wisdom" (5.4). Couldn't we all use somebody like that?