What even is public administration?

I Just read a very short introduction to Public Administration

Our 8-hour, 5-day workweek is the result of a long process dating back to the 19th or 20th century. Social benefits like health insurance and pensions too

We as a society are developing.The work of public administration is interdependent between organizations, but in reality, siloing or gatekeeping of information still exists, even within the same organization.

Communication is key. How top-down and bottom-up communication can work well together.

And yeah, I still don't understand clearly what public administration is as a whole after reading this book. 

Maybe that's not the purpose of this book, and I should find out more. Maybe later.