N. Gregory Mankiw

Nicholas Gregory "Greg" Mankiw (born February 3, 1958) is a famous economist. He graduated from Princeton University and Massachusetts Institute of Technology. He was an economic advisor for President George W. Bush from 2003-2005. In 2006, he became an economic adviser to Mitt Romney. 
Publications.
He wrote a widely used college textbook for economics called Principles of Economics, listing 10 principles that all economies run on:
His economic beliefs were influenced by John Maynard Keynes and he believes in Keynesian economics. He is sometimes labeled as a conservative because he supported George W. Bush's tax cuts and he has criticized the policies of the Obama Administration a few times. He also was influenced by the economist Arthur Pigou who believed that a high tax on something bad for society (called a sin tax) will result in fewer people buying it.