many of the proverbial "modern marvels" and efficient means of production have come about from fairly recent recent technical advances.These include new products,such as hand-held mobile technology devices, as well as new applications of old products,such as guar beans from India now being used in oil and natural gas mining. Thus,much of what we trade today either did not exist or was unimportant in trade a decade or two ago. Why have technical developments increased so much? More than half the scientists who have ever lived are alive today.One reason, of course, is population growth.But another is rising productivity taking fewer hours to produce the same thing-which frees up more people to develop new products because fewer people can produce them.This rising productivity also means that on average people can buy more, including the new product, by working the same number of hours. The entry of new products into the market creates a need for other complementary products (such as cases and apps for smart phones),thus accelerating the need for scientists and engineers.