The Origin and Development of the Moral Ideas is a book by а philosopher Edvard Westermarck. It is one of his main works and a monumental classics study in its field. At the beginning of this book, Westermarck asks why different cultures have different moral views. To answer this question, he decided to acquire first-hand knowledge of the folklore of a non-European people. Thus, he spent four years in Morocco collecting anthropological data, familiarizing himself with the native way of thinking, and understanding local customs. In the result he concluded, he concluded that there is a close connection between moral opinions and religious beliefs.