The many volumes written about the thought of Martin Heidegger (1889-1976) vary not only in matters of interpretation, but also in methodology. Some studies delve into the minutest detail, analyzing specific concepts in particular texts. Another approach aims at grasping in a more general way the movement of Heidegger's Denken, and reflects upon where this path takes us. These broader studies often attempt to survey the entire range of Heidegger"s oeuvre, and usually take some sort of position regarding the development, the shifts in emphasis, or the unity displayed in his writings. Both of these approaches have advantages. The more narrow approach tends to bring out the depth and originality found in each of Heidegger's works. In the broader types of analysis, Heidegger's challenge to the philosophical tradition as a whole and to the modem thinker becomes most evident.