I read this book for my philosophy of history class, and while it was not exactly a pleasurable experience, it has drastically affected the way that I think about science. I have always pictured science as this monolith that moves forward in a constant state of progress. Kuhn introduced me to the idea that science is governed by paradigm shifts that fundamentally change the way scientists understand their discipline. Science changes as anomalies are discovered which the old way of doing science cannot account for. Scientists then switch to new a new paradigm that can account for the anomaly. Since science develops in this manner, it is not necessarily linearly progressing. This explanation is overly-simplified, but it shows the wide difference between what I use to believe and how I think about this topic now.
Evolution and natural selection are two examples of paradigm shifts that have radically altered the way science is done.