Economics 101 by Alfred Mill
This book gives a high-level overview of the subject. It is an easy and quick read that gives you enough background to understand the terms and concepts of economics, and a little of how the economy works.
One challenge in reading most books on economics is that the author is espousing their own view of how things work. Economics is not like physics where the basic facts are agreed. Mill does a good job of presenting a balanced view. There are a few places where his bias shows through but I think that is probably inevitable in this field.
This book is a great basic introduction to economics. I recommend it as a starting point for anyone who is new to the subject.