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A customer fuels her car at an Exxon Mobil gas station in Chicago, Ill. - 

As ExxonMobil battles it out with Apple to be the biggest company in the U.S., we take a look at how the oil giant got to be such a heavyweight.

Author Steve Coll explains the company's political and international policies over the years, how it has dealt with scandals, and what BP could learn from ExxonMobil's past mistakes.

Pulitzer Prize-winning author Steve Coll has just written an extensive profile of the company called "Private Empire: ExxonMobil and American Power."

Follow Jeremy Hobson at @jeremyhobson