From 'hood to boardroom: Would you take career advice from George Bush and 50 Cent?

Get Motivated!" is plastered in large yellow letters at the top of a garishly-designed website. Below this powerful call to arms are various toothy mug shots of motivational speakers. They are all due to appear at a forthcoming seminar for businessmen in Fort Worth, Texas. A sports star here, a bestselling author there, and...hang on – didn't that guy used to be President?

George W Bush's scheduled appearance at the "Get Motivated!" event, to be held next Monday – has prompted chuckles across the world. Not least because the getmotivated.com website is offering tickets for just $19 ("Not Per Person, But Per Office," it keenly proclaims – a far cry from $1,000-a-plate political fundraisers). It's also because the gig is not what Bush expected when he said in 2007 that he would be staving off boredom during retirement by "giving some speeches, to replenish the ol' coffers." At this rate, the coffers may take a while to be replenished.

Bush's public declarations have always been a hoot ("There's an old saying in Tennessee that says fool me once – shame on you. Fool me – you can't get fooled again," he forgettably remarked in 2002). Now, though, there is another motiovational guru on the block. Curtis James Jackson III – aka rapper 50 Cent – has collaborated with the cult author Robert Greene to craft a self-help-cum-cod-philosophy book, The 50th Law. In it, 50 tells how his turbulent life – crack dealer, drive-by victim, hip-hop mogul – can help business overachievers survive the cut and thrust. If you have a penchant for the "don't mess" ethics of Napoleon, you'll probably love it.

The central tenet of The 50th Law, outlined at the beginning of what is a surprisingly hefty, gilt-edged tome, is as follows (and please note Jackson's reference to himself in the third person). "The greatest fear people have is being themselves," he loftily declares. "They want to be 50 Cent or someone else. They do what everyone else does. I lost that fear. And once I felt the power that I had by showing the world I didn't care, I could never go back."

Greene takes 50's loss of fear as the latest example of a long-standing trend in American philosophy, echoing Franklin D Roosevelt's 1933 inauguration speech (made during the Great Depression), when he declared that "the only thing we have to fear is fear itself". Greene and 50 Cent hope that in the world's current state of economic depression, such platitudes (or timeless advice) will be more relevant than ever.

The book is divided into 10 chapters, each written by Greene, though peppered with quotes from the rapper. While reading, a theme quickly emerges. "I was born alone and I will die alone," says 50. "Reality is my drug. The more I have of it, the more power I get and the higher I feel." His mantra, it appears, amounts to little more than putting yourself at the centre of everything you do, of dog eat dog. There is no room for filthy altruism, though that's scarcely surprising if you're learning from a man who began drug dealing at the age of 12 and survived nine gunshot wounds from a drive-by shooting. 50 Cent turned notoriety to his advantage: his 2003 debut album Get Rich or Die Tryin' sold 12 million copies. Now, as head of his own record label, G-Unit Records, and as one of hip-hop's most successful stars, he is worth an estimated $440m. By comparison, Bush is estimated to be worth a far less rap-tastic $25m.

Greene himself is no stranger to rap culture. His 1998 book The 48 Laws of Power ("conceal your intentions"; "crush your enemy") sold 800,000 copies and was praised by hip-hop stars including Busta Rhymes and Kanye West. 50 Cent read it and got in touch.

Ironically, the author praises Louis XIV in The 50th Law, for his most "brilliant manoeuvre" in creating a "cause for the French people to believe in – the greatness and glory of France itself". The king led his country into various wars to extend France's political might (the Franco-Dutch War, the War of the League of Augsburg, and the War of the Spanish Succession, all in the 17th and 18th centuries). "He created impressive spectacles to delight and distract the public from his power moves," writes Greene. Sound familiar? There's a more than a little neo-con behind all that bling. Perhaps George W Bush might want to put The 50th Law on his reading list.

Take it from them: The biz brains

Donald Trump

"Staying well-informed is a daily endeavour. Our world is moving so quickly, it's a challenge to keep up with it, but not to keep up is agreeing to check out. Don't check out, learn everything you can."

Katie Price

"If you want to stay in the business then you've got to be a bit shrewd, haven't you?"

Sandra Bullock

"I love the business and the creative aspects of the business. I don't know if I always want to be in front of the camera. I love producing, I love the camaraderie. I love the stress."

Alan Sugar

"There's only room for one big mouth in my organisation, and that's me."

Duncan Ballantyne

"I don't think Richard Branson would have made all the money he's made if he hadn't been visible. Or Stelios, or Donald Trump, or Alan Sugar. It's become respectable now."

Tamara Mellon

"I was determined to own a global brand. I didn't buy Jimmy Choo just to have a couple of shoe shops in London, did I?"