At a time when Theodore Roethke was finding his poetic voice, he called William Carlos Williams "my toughest mentor." This study examines the discussion about poetry that lives in their correspondence and the poems they sent to each other between 1940-48. From special collections at Yale University and the University of Washington, Robert Kusch has arranged the letters in sequence, and he approaches them both as cultural critic and reader-respondent. Overall, he argues that Williams issued a series of challenges to Roethke, and these challenges changed the direction and scope of Roethke's art. The book has pointed, unconventional advice for teachers of creative writing and for those who are learning the art.