The book "On Classical Economics" by Thomas Sowell explores the history of economic thought during the classical era. It delves into how key economic concepts and tools of analysis emerged and were debated. The book sheds light on the neglected work of Sismondi and John Stuart Mill's impact on economics. It is written in a clear and engaging manner, making it accessible for students studying economics. Overall, "On Classical Economics" offers valuable insights into the development of economic theories and their implications in various areas like price theory, monetary theory, and international trade.