Final answer:
The most appropriate title for Glenn's book on moral principles is 'A Exploring Ethics', as it directly relates to the study of ethics and addresses how humans should behave towards each other, in line with consequentialist, deontological, and virtue ethics.
Step-by-step explanation:
Given that Glenn is writing a book about the moral principles that guide human behavior, the most appropriate title would be A Exploring Ethics. This title reflects the content that is centered on moral principles, which is indeed the study of ethics. Ethics pertains to the rules of behavior that prescribe how a person should conduct themselves and is aligned with the questions of how humans ought to behave toward one another, taking into consideration the various moral frameworks such as consequentialist, deontological, and virtue ethics.
Societal expectations, norms, and legal systems often reflect the shared moral standards, which are commonly debated and discussed in ethical discourse. Influential thinkers like Lawrence Kohlberg have explored this subject in depth, researching how people develop their moral reasoning abilities through stages that reflect varying levels of ethical understanding. In this context, morality and moral development are key aspects of understanding how individuals, societies, and cultures construct their notions of right and wrong.