"Being and Number in Heidegger's Thought" examines the relationship between mathematics and ontology in Heidegger's thought, from his earliest writings, through "Being and Time", up to and including his work of the 1930s. The book charts the unfamiliar territory of Heidegger's conception of mathematics, and explores the relationship between time and number in/Heidegger's magnum opus, "Being and Time". Michael Roubach offers a new analysis of Heideggerian finitude, one of the most recalcitrant problems in the interpretation on "Being and Time". In addition, he situates Heidegger's thought with respect to some of the core debates in logic and the foundations of mathematics.The book goes on to elucidate Heidegger's reading of mathematics as ontology in his writings from the 1930s. Roubach argues that exploring the connection between mathematics and ontology in Heidegger's thought affords us new insight into the origins and evolution of Heidegger's radically original take on the traditional problems of philosophy.This facilitates a reassessment, not only of specific issues in Heideggerian thought, but also of the larger question of Heidegger's place in twentieth-century philosophy.