This book is an outstanding place to start. It addresses a myriad of economic concepts in simple language. It's available for free through the Mises Institute.
"How an Economy Grows and Why It Crashes" by Peter Schiff http://www.amazon.com/How-Economy-Grows-Why-Crashes/dp/04705...
This book gives a simple overview of macro issues and is an interesting and well-presented tale about how economies grow from the basic "man on an island" scenario to a complex market. It also covers Austrian business cycle theory which explains the boom-bust cycle in economies.
Both of these books are from the "Austrian School" of economics, which is named for its Austrian founder, Carl Menger. I find these arguments compelling as they are firmly grounded in logic and are based on the principle that the human individual and her actions form the basis of all economic activity.
The giants of the Austrian school are Ludwig von Mises and Murray Rothbard (highly readable) if you want to seek out more advanced theory.
Also, Sal Khan has this video on the topic: https://www.khanacademy.org/economics-finance-domain/core-fi...