7 The 100 Most Influential Inventors of All Time 7

have the harmful side effects of X-ray or computed
tomography (CT) examinations and is noninvasive, the
technology proved an invaluable tool in medicine.
Mansfield’s research helped transform Lauterbur’s
discoveries into a practical technology in medicine by
developing a way of using the nonuniformities, or gradients,
introduced in the magnetic field to identify differences in
the resonance signals more precisely. He also created new
mathematical methods for quickly analyzing information
in the signal and showed how to attain extremely rapid
imaging.

Robert Kahn and Vint Cerf

respectively, (b. Dec. 23, 1938, Brooklyn, N.Y., U.S.); (b. June 23, 1943,
New Haven, Conn., U.S.)

T

he Internet grew out of funding by the U.S. Advanced
Research Projects Agency (ARPA), later renamed
the Defense Advanced Research Projects Agency (DARPA),
to develop a communication system among government
and academic computer-research laboratories. First,
DARPA established a program to investigate the inter-
connection of “heterogeneous networks.” This program,
called Internetting, was based on the newly introduced
concept of open architecture networking, in which net-
works with defined standard interfaces would be
interconnected by “gateways.”
In order for the concept to work, a new protocol had
to be designed and developed; indeed, a system architecture
was also required. In 1974 computer scientist Vint Cerf,
then at Stanford University in California, and electrical
engineer Robert Kahn, then at DARPA, collaborated on a
paper that first described such a protocol and system
architecture—namely, the transmission control protocol
(TCP), which enabled different types of machines on