Meet your new international man of mystery. We don't know anything about Doc: what his real name is, why everyone calls him Doc, or what he's doing with all those babies in jars. Where was he before he came to Cannery Row? Where did he grow up? Why has he always wanted to try a beer milkshake?
Doc owns Western Biological Laboratories, a business that supplies sea life in bulk to universities and anyone else who wants it. It's a living, but he also does it because he's super interested in the variety of life out there in the tide pools. This tells us that he's a curious, open-minded guy—which may explain why he's so kind to the variety of life hanging out just outside his door.
Everyone in Cannery Row likes Doc. Even Mack, who seems to spend most of his time trying to get other people to do stuff for him (like let him live at the Palace) announces, "That Doc really is a fine fellow. We ought to do something for him" (2.29). He's popular with the ladies—he's got "three four dames" who visit the lab (7.18), and he's friend to everyone in town.
But despite all his friends, he's still a lonely guy who spends a lot of time by himself listening to music, sometimes on the phonograph and sometimes in his head. He's a "lonely and set-apart man" (17.1)—and everyone notices it.
Doc may not be a medical doctor, but he's the closest thing to one in Cannery Row. When he's not out collecting starfish or what-have-you, he can usually be found helping out some or another Cannery Row resident. He's the guy people call when they have a toothache or when their kid is sick. Mack even calls him when his dog is sick. During the influenza epidemic, Doc is the most popular guy around:
It was not his fault that everyone in the Row came to him for medical advice. Before he knew it he found himself running from shanty to shanty taking temperatures, giving physics, borrowing and delivering blankets and even taking food from house to house. [ . . . ] Doc didn't get much sleep. He lived on beer and canned sardines (16.4)
Why is Doc the guy everyone goes to for medical advice? Well, he's been to college, so he might seem like the most likely person to know what to do. Plus, he's a scientist of sorts, so he has all kinds of things that can be used as medicine, like laudanum.
But, you know what? We bet it has a lot more to do with how he acts than what he knows. He cares for the people of Cannery Row, and he respects them when no one else does. He calls Mack and the boys "true philosophers" who are "healthy and curiously clean" (23.11). Cannery Row's residents seem to instinctively trust Doc. Even though he's got babies in jars.
What we can't quite figure out is what's in it for him. We're never told outright that, say, Doc gets a sense of satisfaction (or an ego trip) from helping out like this, just that he feels obligated in some way to help out when someone asks. He started helping with the flu epidemic and "before he knew it" he was running himself ragged. In fact, all he seems to get out of Cannery Row is a lot of obligation and a trashed lab.
If Doc gets anything out of all this, it's that everyone in Cannery Row is indebted to him. Even Lee Chong owes Doc big time. Mack reminds him of this: "'He's such a nice guy. Hell, when your wife had that bad tooth, who gave her the laudanum?' Mack had him. Lee was indebted to Doc—deeply indebted" (20.11-20.12).
Sure, debt and goodwill aren't much use to him. It's not like he can cash it in and retire to Palm Springs to open an ice cream parlor. And he even ends up having to pay for most of the party at the end. So, is he selfless? Is he just in it for the pure joy of helping other people?
We might point out that Doc doesn't really owe anyone else anything. Everyone else in Cannery Row (even Lee Chong) owes something to someone else, while Doc is the only guy who's debt-free. If the community is held together by these debts, then Doc stands outside the community a little bit, even though he's so important to it.
Doc's strengths include, well, strength, and his deep commitment to the people around him. He loves and respects all the weirdoes on Cannery Row, and they love and respect him back. If he has a weakness (apart from being afraid of getting his head wet), it's that he doesn't get how bummed Mack and the boys are after their big party foul:
Doc didn't know the pain and self-destructive criticism in the Palace Flophouse or he might have tried to do something about it. And Mack and the boys did not know how he felt or they would have held up their heads again. (23.28)
How could he live day in and day out in Cannery Row without realizing this? Well, because as much as he likes and respects them, Doc isn't really one of them.
If Doc changes much over the course of the book, Steinbeck doesn't hit us over the head with it. He's as kind, well-loved and lonely at the beginning as at the end, and we never hear about how the party affects him. Does it show him how important he is to the community? Is the nostalgic poetry he reads during the party (and finishes alone the next day) a way of saying goodbye to Cannery Row, even as he is becoming aware of just how cool a place it is?
We propose that it doesn't matter.
Yeah, Doc is the most important character. But he's the most important character not because he has the best character arc or because he overcomes the coolest villain. He's the most important character because he helps Cannery Row change. They all work together to throw him the party of the century, and Mack—who we think might be the real protagonist here—has grown up a little. So as Doc cleans up the next morning, he realizes that his role in the novel is done.
It might help to remember what Doc does for a living. Pause for a second to check out the "Symbols" section about the Great Tide Pool. (Don't worry. We'll wait.)
Okay, good. So now you know that the Great Tide pool is an image of Cannery Row: all the different animals in their habitats, living, reproducing, fighting and dying underwater are just like the characters up on dry land. And where is Doc in all this? He's not among the crabs and the starfish, he's up above, observing.
In other words—Doc is like our narrator, hovering above the characters to give shape and meaning to their stories, but never quite fitting in. Makes you feel a little sad for Steinbeck, doesn't it?
Cannery Row is dedicated to some guy named Ed Ricketts, and Ricketts was the real-life model for Doc. (And can we just say? No wonder he had three or four dames wandering around his lab.)
Steinbeck used to hang out with him at his (real) lab in Cannery Row, listening to music, talking philosophy and drinking beer. Ricketts was apparently as cool as the fictional Doc, welcoming people into his home and sharing his love of marine ecology with anyone and everyone. Want to know more, including Ricketts's tragic end? Check out "Best of the Web."