A question from Yahoo! Answers:

Why are some countries rich and some are poor?

Because some countries have institutions that are not conductive to growth and development. Richard Roll wrote a well-researched paper on the subject that includes a literature review and his original contributions to the polemic:

http://www.anderson.ucla.edu/documents/a…

Other researchers of interest are Daron Acemoglu, William Easterly, and Dani Rodrik.