A single theory describing nature’s four forces, called the “Theory of Everything,” has been the Holy Grail for physicists and other scientists seeking the universe’s deepest mysteries. Physicist Juan Maldacena has devised a way to explain gravity using a theory that also explains the other three basic forces of nature. And in this day of high-tech gadgets growing ever smarter and more powerful, Maldacena’s breakthrough came not with the help of giant particle accelerators, complex computer programs, or powerful telescopes. Instead, Maldacena relied on two ancient tools: pen and paper. “I use computers sometimes, for e-mail or for exchanging information with colleagues,” Maldacena said. Maldacena is a specialist in the branch of physics called string theory, which posits that the universe is actually made up, not of particles as is commonly understood, but of vanishingly small strings that create different particles when they vibrate at different frequencies. It was through string theory that Maldacena found what could be the link between gravity and the other three forces: strong, weak, and electromagnetism.