This collection of more than two dozen essays by philosophy scholars of international repute traces the profound impact exerted by Husserl's Meisterwerk, known in its shortened title as Ideen, whose first book was released in 1913. Published to coincide with the centenary of its original appearance, and fifty years after the second book went to print in 1952, the contributors offer a comprehensive array of perspectives on the ways in which Husserl's concept of phenomenology influenced leading figures and movements of the last century, including, among others, Ortega y Gassett, Edith Stein, Martin Heidegger, Aron Gurwitsch, Ludwig Landgrebe, Dorion Cairns, Simone de Beauvoir, Jean-Paul Sartre, Maurice Merleau-Ponty, Jacques Derrida and Giles Deleuze.