Built what was the biggest ad agency business in the world until a recent merger of rivals unseated it, Sir Martin Sorrell is a man worth reading up on.
Here is an interview with him http://howdidtheydoit.net/business-2/sir-martin-sorrell-ceo-wpp/
If you’re in the business of marketing, his reviews of the state of things are essential reading. Have a look at the WPP site for more info and to download or order a copy of the annual report. http://www.wpp.com/wpp-annual-report-2012.pdf