What really happened to Tesla's "death ray"? An engineering deep-dive from the 1937 memorandum to modern laser weapons. In 1934, Nikola Tesla announced a weapon that would end all wars: a particle beam capable of destroying aircraft at 200 miles. The press called it the "death ray." When Tesla died in 1943, the FBI seized his papers. What did they find? This book answers that question with physics, not mythology. What You'll Discover: The Technical Truth: Why Tesla's macroparticle beam was doomed by atmospheric drag-but why his fundamental insight was correct. The Physics: Complete analysis of electrostatic acceleration, beam divergence, and why photons beat particles for directed energy weapons. The Declassified Files: What the FBI, Naval Intelligence, and Soviet Union actually found in Tesla's papers. The Modern Reality: How Tesla's vision evolved into operational laser weapons-LaWS, HELIOS, Iron Beam-destroying drones in the Persian Gulf today. The Unexpected Legacy: How particle beam physics saves lives in hospital proton therapy centers worldwide. Complete Coverage Includes: - Tesla's 1937 technical memorandum (full engineering analysis) - Particle accelerator physics and why it works for medicine, not weapons - Einstein's 1917 prediction that made lasers possible - The $30 billion Strategic Defense Initiative (SDI/Star Wars) - HAARP: separating science from conspiracy with actual physics - The future: megawatt laser weapons and space-based DEW systems This is NOT another Tesla mythology book.It's an honest engineering assessment written for the educated general reader. Every equation is explained. Every claim is sourced. The goal is truth, not hero worship. Perfect for: Engineering students, defense technology enthusiasts, physics readers, and anyone tired of Tesla conspiracy theories. Includes:7 technical diagrams, 4 appendices (timeline, equations, glossary, references), 14 chapters across 6 parts, 35,000+ words of original analysis.