"I am often troubled by the enormity of having undertaken to explore two crafts instead of one, two difficult crafts, each of which could command a lifetime's imagination and effort. But there are some things the novel can do which poetry cannot do; lyric poetry is concerned chiefly with the moment's intense vision, the vision of one person; the novel is concerned with the inter-relation of several -and sometimes many- psyches and their impact on each other. It is concerned with growth. A novel requires a long breath, un long souffle as the French would say. It can, to some extent, be planned ahead over a considerable period of time. One can say, "I am going to write a novel next year," but one cannot say, "I am going to write a poem next year." Intellect and will do not control poetry to the same extent."
From Writings on Writing by May Sarton (1980)