For decades the Soviet Union and now Russia have held leading positions in the development of a special class of vehicles that are neither aircraft nor ships or both at once. Known as wing-in-ground effect (WIGE) craft or by their Russian name of ekranoplan, these vehicles combined the best of both worlds, operating on the borderline between the sky and the sea, offering the speed of an aircraft coupled with better operating economics and the ability to operate pretty much anywhere on the world's waterways. As such they promptly attracted the attention of the military and thus have been veiled in secrecy until recently. The book describes in detail the many series of WIGE vehicles developed by various design bureaus, including the Orlyonok, the only ekranoplan to see squadron service, the missile-armed Loon and the famous and awesome KM, or Caspian Sea Monster, which first attracted the attention of the West to these developments.