Pioneer aviation engineer (1889–1972) who developed the first four-engine airplane and the first modern helicopter to be put into widespread use. Two hardcover books, each signed on the first free end page by Sikorsky: The Story of the Winged-S (ins) and The Invisible Encounter (no dustjacket). In fine overall condition with light toning to the pages of wear to the first book’s dustjacket. RRAuction COA.
