An expert account of the development, role, and capabilities of the S-300 and S-400 air defence missile systems, key strategic weapons in Putin's Russia. Few modern missile systems have had such significance as the S-300 family. Highly regarded technically, Russia's most powerful air-defense systems have been a major strategic asset to the country, exported to major powers around the world, and are a key weapon in many international hotspots and in recent wars. In this book, professional missile systems analyst Steve Zaloga uses his specialist knowledge to assess and analyse them in detail. He explains that the S-300 is, in fact, three systems: the S-300P, designed as a replacement for older Soviet strategic SAM systems, the S-300V, developed to defend against Pershing ballistic missiles, and the S-300F, designed for ship defense. He also considers the supplementary S-350 system and the new-generation S-400 system, deployed in Syria and sold to both China and Turkey. An assessment of the latest S-500 system, designed to counter ballistic missiles and hypersonic cruise missiles, is also provided.