“the most powerful contributor was science. “It is knowledge that is the key,” Deaton argues. “Income—although important both in and of itself and as a component of wellbeing . . .—is not the ultimate cause of wellbeing.”16 The fruits of science are not just high-tech pharmaceuticals such as vaccines, antibiotics, antiretrovirals, and deworming pills. They also comprise ideas—ideas that may be cheap to implement and obvious in retrospect, but which save millions of lives. Examples include boiling, filtering, or adding bleach to water; washing hands; giving iodine supplements to pregnant women; breast-feeding and cuddling infants; defecating in latrines rather than in fields, streets, and waterways; protecting sleeping children with insecticide-impregnated bed nets; and treating diarrhea with a solution of salt and sugar in clean water.”