Other sports have captains, but nowhere is the designation more significant than in the NHL.
For one thing, captains take a tangible role in having officials talk to them about things like official rulings and other team messages. But it is so much more than that.
Arguably, no team sport relies as much on team chemistry. Hockey has few "plays" and teams must read and react off one another to unexpected things on the ice.
The NBA also has that, but players' resulting movements are more natural than on ice skates and an individual player can score in isolation much more easily. Thus, fewer NBA players have more impact on those teams.
The team concept is deeper in the NHL. It is why teams do more things together, from young players living with veterans to the whole tradition of teams growing playoff beards.
That makes the captain more needed, and hence his selection is more represented: Joe Thornton wears the "C" on his sweater for the San Jose Sharks, and the word "captain" is almost as likely to be said as not when his name is mentioned.
So who are the greatest captains in each team's history?
Historical accounts from others have biases that make them unreliable. Thus, I am hardly qualified to answer that for teams whose history predates my own hockey viewership.
I saw little hockey before 1989, the beginning of the Wisconsin Badgers Drive for Five title season. Living in a non-NHL metro area, I saw little NHL hockey for the decade that followed.
But almost no one is really qualified to say how much a given player meant to his team anyway. Can anyone really tell how much difference one captain to another meant to his team on the ice and off it?
We know enough to look for three things: Stanley Cup titles (or other playoff successes for those franchises without them), regular-season team success and individual production.
Those measurements can be enhanced, but what we see with our own eyes when we are old enough to understand the context of the situation matters most. By those standards, here is the best all-time captain for Anaheim through Detroit, with others to follow.