This book contains a systematic investigation of the ethics from a scholastic standpoint. It begins by examining the fundamental theory of action. After that the author develops the conceptions of duty and laws as concrete duties. Finally the book examines social ethics as embracing all the rights and duties of men in their relations with other men, both as individuals and as groups, either in the family or in the state. The author offers a very comprehendible text that can be read with profit by undergraduates.