This collection of prose and poetry elaborates on themes explored in Roubaud's Some Thing Black, which the Times Literary Supplement called "a harrowing book . . . an elegy for our time." As in the earlier collection, Roubaud grapples with the grief he continues to feel at the untimely death of his young wife.

In parts 1 and 2, he uses the possible existence of many worlds as a means by which to transcend the trauma of this unbearable loss. (David Lewis's book On the Plurality of Worlds provided the inspiration and title for Roubaud's book.) These poems also rage against the limitations of poetry itself, which can only clarify the exactness of his grief, not assuage it. In part 3, Roubaud uses a mathematically precise form to explore the idea of form.

As a meditation on both grief and on poetry, The Plurality of Worlds of Lewis is a memorable achievement.