Nikola Tesla invented or developed many of the electrical technologies which form the basis of modern life, including: alternating-current (AC) power transmission and electric motors; high-frequency (HF) communications, the basis for radio and television; neon lighting; remote radio-control; and X-rays. But his visionary genius and technical skill was countered by his lack of business acumen and eccentric personality. After dying penniless in 1943, his "missing papers" regarding the construction of a 'death ray' became the focus of international intrigue. His research on particle beam weapons led to several American and Soviet military research programs, including the Strategic Defense Initiative, known as SDI or "Star Wars".