Back in 2001, William Kamkwamba was a semi-educated 14-year-old Malawian who had been forced to drop out of secondary school when, during a terrible drought, his parents could no longer pay for him to go. This week, he has been in California and Chicago on a whirlwind book tour, hailed as a "genius" and appeared on TV chat shows. He has been the toast of international technology conferences, lauded by Al Gore and environmentalists and shared a stage with Bono and Google co-founder Larry Page - as well as co-writing a book about his life, with journalist Bryan Mealer.

When Kamkwamba stopped going to school because his family could no longer afford the fees, he went to his local library, read up on his science, found a DIY (do-it-yourself) guide to making a wind generator and set about trying to build it. Using a tractor fan, shock absorbers, PVC pipes, a bicycle frame and anything else he could lay his hands on, he then built a rudimentary wooden tower, plonked his home-made generator on the top, and eventually got one, and then four bulbs to light up. He is now known as "the boy who harnessed the wind" - the title of his book.

"I managed to teach myself about how motors and electricity worked. Another book featured windmills on the cover, and said they were used to pump water and generate power. I was so inspired I began collecting scrap metal and old bicycle and tractor pieces. Many people, including my mother, thought I was crazy," he wrote in his blog this week.

Kamkwamba is presented to the west as the "humble hero", an extraordinary Malawian who has overcome everything to improve his family's situation, but the reality is that most of Africa, India and the developing world depends on equally innovative and inventive people coming up with ways to make a living with no cash and next to no resources.