I am going to be talking about a chapter speaking on management duties. I myself plan on working in human resources. But I do not understand what a black letter law is? And I dont know what black letter law I can talk about that refers to business, management, and duties.

Can someone explain to me:

1)What a black letter law is?

2) A list of 4 different black letter laws that can relates to business.

3)An explanation/description of the listed black letter laws listed.

Thank you!