Nikola Tesla was an inventor and physicist who is best remembered for his contributions to the AC power system and radio, but he may have also built a death ray. At a 1937 luncheon in his honor, Tesla claimed to have created a weapon that could shoot a concentrated beam of energy capable of bringing down fleets of airplanes. He further claimed to have built, demonstrated, and used this weapon. When Tesla entered negotiations with the U. S., the United Kingdom, and the Soviet Union to sell his device, Tesla claimed that one of these parties had sent people to break into his room and steal his invention, but that this theft was impossible since the blueprint for the weapon was entirely in his mind. Unfortunately, Tesla died with the blueprint in his mind before anyone could get one. On second thought, maybe that’s not such a bad thing. What is the central idea of this passage?