The early explorers sailed into a void not knowing what beasts, storms or cliffs might await their travels. Their shear audacity and pluck carried them through their adventures. The Gemini program is the equivalent for space travel and David Harland gives a great recount in his book ,How NASA Learned to Fly in Space. He takes the reader on a rollicking good drama of the pilots and support crew as their space vessels sail through the uncharted realms toward the stars.