Sharon Thesen provides a fascinating run-down of the long poem's seemingly limitless range and abilities:
Long poems are often stories, explorations, or accounts of one sort or another; and in this way long poems participate in the prose tradition of writing; indeed, many long poems are written in prose stanzas or prose sentences—I’m thinking of writers like Daphne Marlatt, Roo Borson, Sarah de Leeuw. Long poems can be poems about stories. They can fictionalize the “I” of the poem, as in persona poems; and use unreliable narrators, such as Ondaatje’s Billy the Kid. While not being narrative poems as such, in the epic sense, most long poems do engage narrative as a mode or energy that propulses them forward, as in filmic montage. There is something filmic, performative, and theatrical about the long poem, which also collects the long poem into the traditions of ritualistic verse drama, itself deconstructed in Poet’s Theatre texts popular among the American language poets. In Canada, Patrick Friesen’s work comes to mind; in England, Alice Oswald’s. Indeed, her book length poem Dart is I think one of the most astonishing and satisfying book-length poems—a poem about a river and those who live with it, beside it, on it, in it. She researched for years, interviewing and recording the voices of the riverside dwellers—fishermen, trappers, farmers, kids, vagrants, and others. The long poem’s capaciousness and adaptability extends to its use of genres such as biography and investigative journalism deploying historical documents. The American poet Ed Sanders, who writes what he calls “investigative poetry,” has written verse biographies of Allen Ginsberg and Anton Chekhov, as well as verse biographies of the year 1968 and of the history of America. These are fascinating because of Sanders’ typically engaged, lyric, subjective, opinionated voice. In a similar way, Nourbese’s Zong “documents” the massacre, in 1781, of 150 African slaves who were thrown overboard as surplus cargo during transport to England. Inarticulacies and silences render the unspeakable unspeakable; as does Sakiklar’s Children of Air India with its imposition of redactions, its incompletenesses, its rumours. This is like detective work, forensic work upon cultural memory.