Most of Muldoon's collections contain shorter poems with an inclusion of a long concluding poem. As Muldoon produced more collections the long poems gradually took up more space in the volume, until in 1990 the poem "Madoc: A Mystery" took over the volume of that name, leaving only seven short poems to appear before it. Muldoon has not since published a poem of comparable length, but a new trend is emerging whereby more than one long poem appears in a volume.