Thomas S. Kuhn's The Structure of Scientific Revolutions is perhaps the best-known work in HPS. One of the first to apply a study of history to problems within the philosophy of science, Kuhn looked at the possibility of giving a rational account of theory change; that is, why have some theories replaced others over time? Some philosophers thought (and think) that we can explain theory change in a progressive way by saying that theories are supplanted by better ones (whether that means more parsimonious, truthlike, instrumentally successful, or any of the other proposed ways to demarcate between theories). Kuhn demonstrated that social factors have an important role to play in analysing the history and philosophy of science, using the term "paradigm" to refer to the way in which commonly held concepts, theories and practices can become entrenched, such that a theory being "better" than the alternatives is not enough to immediately overturn the investment of time, effort, conviction, and so on, that has been put into the orthodoxy.
Kuhn's work led to the development of the field of SSK (the Sociology of Scientific Knowledge) and a general broadening of the philosophy of science to include all those factors (aesthetic, social, thematic, political, rhetorical) that had traditionally been ignored or had their importance minimised. It helped that he was already known as the author of The Copernican Revolution, acknowledged as a masterpiece within the history of science. This account of the rise and development of Heliocentrism forever replaced the mythical of reason against dogmatism with a sophisticated appreciation of how theory, experiment, theology, society and politics interacted. The significance of Kuhn remains this legacy of the sheer complexity of scientific practice.