The expression of emotions in man and animals

About “The expression of emotions in man and animals”

Charles Darwin wrote about expression in his work, focusing on the recognition of character through permanent facial features. He noted that more writings exist on physiognomy than on expression. However, he was not addressing physiognomy in this work. Darwin consulted older treatises but found them of little help. He mentioned that the 1667 work "Conferences" by the painter Le Brun is the best-known ancient text on the subject and contains some useful observations.