A mobile phone (also known as a cellular phone, cell phone and a hand phone) is a device that can make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile phone operator, allowing access to the public telephone network. By contrast, a cordless telephone is used only within the short range of a single, private base station.

In addition to telephony, modern mobile phones also support a wide variety of other services such as text messaging, MMS, email, Internet access, short-range wireless communications (infrared, Bluetooth), business applications, gaming and photography. Mobile phones that offer these and more general computing capabilities are referred to as smartphones.

The first hand-held mobile phone was demonstrated by Dr Martin Cooper of Motorola in 1973, using a handset weighing around 1 kg. In 1983, the DynaTAC 8000x was the first to be commercially available. In the twenty years from 1990 to 2011, worldwide mobile phone subscriptions grew from 12.4 million to over 5.6 billion, penetrating the developing economies and reaching the bottom of the economic pyramid.

Devra Lee Davis is an American epidemiologist and writer. She was born on June 7th, 1946, in Washington, DC, the daughter of Harry B. and Jean Langer Davis, and was raised in Donora and Pittsburgh, Pennsylvania.

Her career has spanned all areas of academia, public policy, and scientific research. While Senior Advisor to the Assistant Secretary for Health in the Department of Health and Human Services, she counseled leading officials in the United States, United Nations, European Environment Agency, Pan American Health Organization, World Health Organization, and World Bank.

She has also authored more than 190 publications in books and journals ranging from the Lancet and Journal of the American Medical Association to Scientific American and the New York Times and blogs in Freakonomics for the New York Times, Huffington Post and elsewhere.

Davis graduated from Taylor Allderdice High School and later received a B.S. from the University of Pittsburgh in 1967. A former Scholar in Residence at the National Academy of Sciences, she completed her Ph.D. in science studies at the University of Chicago as a Danforth Fellow, and an M.P.H. at Johns Hopkins University as a National Cancer Institute post-doctoral fellow.