Jane Hirshfield is the author of six collections of poetry, including After, Given Sugar, Given Salt, The Lives of the Heart, and The October Palace, as well as a book of essays, Nine Gates: Entering the Mind of Poetry. She edited and co-translated The Ink Dark Moon: Love Poems by Komachi & Shikibu, Women of the Ancient Court of Japan, Women in Praise of the Sacred: 43 Centuries of Spiritual Poetry by Women, and Mirabai: Ecstatic Poems. Her work has appeared in many publications including The New Yorker and The Times Literary Supplement. In 2004, Hirshfield was awarded the 70th Academy Fellowship for distinguished poetic achievement by The Academy of American Poets, an honor formerly held by such poets as Robert Frost and Elizabeth Bishop.

Sean Carroll is a theoretical physicist at the California Institute of Technology. His research focuses on theoretical physics and cosmology. Carroll is the author of From Eternity to Here, about cosmology and the arrow of time, has written a graduate textbook, Spacetime and Geometry: An Introduction to General Relativity, and recorded a course on dark matter and dark energy for The Teaching Company. He is a contributor to the group blog Cosmic Variance.