The development of rocket technology is a story of international accomplishment. It is also the story of three men working independently in three different countries who were at the forefront of liquid-fueled rocket development. All three wrote extensively on the theory and design of rockets and their potential. All three used models for testing of some kind. Two developed and tested actual rockets. Due to political constraints, the work of each was not known to the others, yet we know from their writings that all arrived at similar conclusions at the start of the twentieth century.