"An original contribution to our understanding of a very difficult segment of Heidegger's writings. Daniela Vallega-Neu is clearly one of the leading experts on this period of Heidegger's work, the period of the "poietic" or "nonpublic" texts."—David Farrell Krell, author of, Ecstasy, Catastrophe: Heidegger from Being and Time to the Black Notebooks"Daniela Vallega-Neu's book is a landmark achievement in Heidegger scholarship. It offers a coherent and incisive developmental account of some of the central notions in Heidegger's private notebooks of the 1930s and 1940s. Vallega-Neu displays a rigorous, thoughtful, and nuanced understanding of the whole of Heidegger's notebooks. She tells a compelling tale of the changes in Heidegger's thought at this time."—Andrew J. Mitchell, author of, The Fourfold: Reading the Late Heidegger