In 1959, Leo Strauss said: “the only great thinker in our time is Heidegger.”
The full, disturbing context for that statement:
“All rational liberal philosophic positions have lost their significance and power. One may deplore this, but I for one cannot bring myself to clinging to philosophical positions which have been shown to be inadequate. I am afraid that we shall have to make very great effort to find a solid basis for rational liberalism. Only a great thinker could help us in our intellectual plight. But here is the great trouble: “the only great thinker in our time is Heidegger.” (RCPR, p. 29)
Related: My primer on Heidegger’s basic philosophy, in the Philosophers, Explained series. My discussion of Heidegger’s significance for postmodernism is in Chapter 3 of Explaining Postmodernism.