Takeaway: Culture is the result of a wide variety of influences.
Thomas Sowell is an economist. I have read three of his economics book (Basic Economics, Applied Economics and Economics Facts and Fallacies). These books, while clearly from a conservative approach to economics were focused on education and not propaganda. I would recommend any of the three books to help you understand how economics works. (Basic Economics is an intro to economics, Applied Economics focuses on national level and Facts and Fallacies is more focused on countering bad economic thinking at many levels).
Conquests and Cultures is the third book in a series of historical exploration of culture. (Race and Culture and Migration and Culture are the first two). These are historical looks at culture using Sowell’s common tools of economic and broad level research.