Tim Hartford is engaging and entertaining. His book and column on Slate show the reasoning of an economist as he interprets and explains the world around him. It’s much more compelling than any textbook introduction to microeconomics.

You can buy The Undercover Economist at:
http://www.amazon.com/Undercover-Economist-Exposing-Poor-Decent/dp/0195189779/ref=pd_bbs_sr_2/103-0235482-0843044?ie=UTF8&s=books&qid=1185570333&sr=8-2

His recent Slate articles on the impact of market designs are also interesting
• The design of fish markets: http://www.slate.com/id/2168743/fr/flyout
• Auctions on eBay: http://www.slate.com/id/2166662/