Kuhn, especially in The Structure of Scientific Revolutions, has had a massive impact on the philosophy of science. His historicist approach has definitely brought to attention the sorts of unexamined beliefs inherent in the development of science. His emphasis on historical contingency places him squarely in opposition to Popper regarding how science makes progress. I think this appreciation of contingency is the useful part of Kuhn's work, but that the instruments he uses - the binary opposition between "normal" and "revolutionary" science are too crude. There seem to be plenty of occasions in science where beliefs - even fundamental ones - are examined and re-worked, without an actual paradigm shift - occasions which seem more than the tinkering associated with normal science and less than the Gestalt shift of revolution. Also, his doctrine of the incommensurability of paradigms seems problematic - how does a new paradigm arise? It seems to preclude the very real discourse which occurs within a discipline during a time of crisis or revoultion - people do seem able to communicate across paradigms. Some of his paradigmatic paradigm shifts are a little crudely drawn, too - the often cited relativity vs Newton case was actually a good deal more "organic" in its genesis than Kuhn acknowledge, for example. Kuhn, like Foucault in The Order of Things, is keen to be a historicist, but seems to play a little fast and loose with the history in order to do so. A top book, but it should be read in conjunction with some Popper or Lauden to give some balance.