This, The Discourse of Nature in the Poetry of Paul Celan: The Unnatural World by Rochelle Tobias, is, according to Henry Sussman, a "major achievement in the study of Paul Celan's poetry, above all in the field of close exegesis and the cultural ethics and politics implicated by close reading" and it looks very interesting:
Paul Celan has long been regarded as the most important European poet after 1945 but also the most difficult owing to the numerous references in his work to his personal history and to a cultural heritage spanning many disciplines, centuries, and languages. In this insightful study, Rochelle Tobias goes a long way to dispelling the obscurity that has surrounded the poet and his work. She shows that the enigmatic images in his poetry have a common source. They are drawn from the disciplines of geology, astrology, and physiology or what could be called the sciences of the earth, the heavens, and the human being. Celan’s poetry borrows from each of these disciplines to create a poetic universe — a universe that attests to what is no longer and projects what is not yet.
This is the unnatural world of Celan's poetry. It is a world in which time itself takes physical form or is made plastic. Through a series of close readings and philosophical explorations, Tobias reflects on the experience of time encoded and embodied in Celan's work. She demonstrates that the physical world in his poetry ultimately serves as a showcase for time, which is the most elusive aspect of human experience because it is based nowhere but in the mind. Tobias's probing interpretations present a new model for understanding Celan's work from the early elegiac poems to the later cryptic texts.