This collection is composed of correspondence that Mitchell Sharpe initiated during research on his thesis, The Novels of Waldo Frank: A Search for the American Form in the 1950's, and later during his research on rocket engine development and and space flight in the 1960's and 1970's. This later research culminated in several books on rocket development and space technology. The letters are arranged in chronological order and comprise correspondence Sharpe received while researching his thesis and books. They consist of two letters from Waldo Frank and one letter from John Dos Passos. Included are letters pertaining to Sharpe's research on Robert Goddard, the rocket engine pioneer about whom Sharpe wrote a biographical sketch and which are primarily from Esther Goddard (Mrs. Robert Goddard) and span the years 1964-1970, a collection of letters regarding early rocket engines, World War II missile-based weaponry, Russian space tracking systems, and American space flight and span the years from 1963 to 1973. Also included are letters which center around Wernher Von Braun and rocket development at Peenemude, the site of the rocket research and development laboratory in Nazi Germany, along with letters from Von Braun, Walter Dornberger, and K. A. Ehricke, German rocket scientists, and Albert Speer, SS Armaments Minister, which span the years from 1965 to 1975.