Can there be more than one narrator telling a story?

What rmhope says about the "frame story technique" is certainly true. I was reminded by her answer of two stories frequently covered by . They are "The Adventure of the Speckled Band" and "The Red-Headed League." In both these Sherlock Holmes stories the main narrator is Dr. Watson, as is the case in nearly all Sherlock Holmes stories. But both "The Adventure of the Speckled Band" and The Red-Headed League" begin with extremely long back stories told by the clients.

In "The Adventure of the Speckled Band," Helen Stoner tells Holmes and Watson about her mother and stepfather, their lives in India, her mother's death, her mother's will, her stepfather's bad temper, about her sister Julia's strange death, and many other things. It is a story within a story. The same is true with Jabez Wilson, who tells Holmes and Watson all about his pawn shop business, his assistant, his going to work for the Red-Headed League, the dissolution of the League, his search for Duncan Ross, and many other things. In both cases the back stories become so interesting that the reader may forget they are only stories within the stories. The same is true with Henry Baker and his story of the lost goose in "The Adventure of the Blue Carbuncle."

So I guess a story can have more than one narrator if it is handled adeptly. I suppose a story could even have a story within a story within a story--although the poor writer might go crazy handling the punctuation, It is interesting to observe the punctuation in the openings of both "The Adventure of the Speckled Band" and "The Red-Headed League." For example:

“ ‘I wish to the Lord, Mr. Wilson, that I was a red-headed man.’ ”

“ ‘Why that?’ I asks.”

“ ‘Why,’ says he, ‘here's another vacancy on the League of the Redheaded Men. It's worth quite a little fortune to any man who gets it, and I understand that there are more vacancies than there are men, so that the trustees are at their wits' end what to do with the money. If my hair would only change colour, here's a nice little crib all ready for me to step into.’ ”

Note the single quotes within the double quotes, even when Wilson is quoting himself. Note the punctuation of "'Why,' says he, 'here's... This can get kind of tricky. But Sir Arthur Conan Doyle was a meticulous writer and a good model.