As a scientist, Kaku, a professor of theoretical physics at the City University of New York, has done important work on string theory, which tries to reconcile Einsteinian relativity and quantum mechanics by proposing that the fundamental units of nature are incredibly tiny strings of energy [sources: PBS, Smith]. But Kaku is better known as a bestselling author with an ability to explain science and technology and to discern the trends evidenced by recent discoveries and inventions.
In his 2011 book, "Physics of the Future: How Science Will Shape Human Destiny and Our Daily Lives by the Year 2100," Kaku relies heavily on the "Delphi poll" method, informally surveying experts in various scientific fields, and even visiting their laboratories to study prototypes of inventions that already exist in an effort to predict future game-changing developments [source: Kaku]. Based on that data, Kaku envisions a future society with technologies that would seem like science fiction fantasies today.
He predicts that computers will be able to read our minds, which will give us the power to move objects and machines by thinking about them. He also predicts advances in biotechnology that will enable humans to extend their own life span and to fashion new organisms not found in nature. And nanotechnology will give us the ability to take an object or material and tinker with it at the molecular level to convert it into something completely different, fulfilling the dreams of medieval alchemists who searched for a way to turn lead into gold. Moreover, Kaku envisions national differences eventually fading by 2100, so that the world develops a single, planetary civilization [source: Kaku].