Bernard, a famous British scientist and one of the founders of science of science, once outlined a set of dynamic images for science: (1) an organizational system; (2) a method; (3) an accumulated knowledge tradition; (4) A major factor to maintain or develop production; (5) One of the most powerful forces that constitute our beliefs and attitudes towards the universe and mankind. Among them, science, as an organizational system and as a factor of production, only appeared after modern times. But what's so special about science? What is the "scientific method" that leads to particularly commendable or reliable results? The author Chalmers wrote this book to try to explain and answer such questions. After reading Chalmers' What is Science for nearly a month, the author guided us to systematically understand the academic thoughts of various scientific philosophers on scientific problems, scientific research processes and experiments, observation and reasoning. And has carried on the critical thinking to these thoughts. This is a great inspiration to my understanding of science. The author does not study the concrete content of science, but studies "science" directly as an object from a philosophical perspective. In the book, the author introduces the most influential philosophers of science in the 2th century, such as Popper, Kuhn, lakatos and Fei.