Mark Doty has always felt haunted by Walt Whitman's bold, new American voice, and by his equally radical claims about body and soul and what it means to be a self. In What Is the Grass, Doty--a poet, a lover of men, a New Yorker, and an American--keeps company with Whitman and his mutable, landmark work, Leaves of Grass, tracing the resonances between his own experience and the legendary poet's life and work. What is it, then, between us? Whitman asks. Doty's answer is to explore spaces tied to Whitman's life and spaces where he finds the poet's ghost, meditating on desire, love, and the mysterious wellsprings of the poet's enduring work. How does a voice survive death? What Is the Grass is a conversation across time and space, a study of the astonishment one poet finds in the accomplishment of another, and an attempt to grasp Whitman's deeply hopeful vision of humanity.