Master Countdown, [Gemini] Launch Vehicle, SLD, GLV-12. Martin Co., 10 October 1966. 4/so. Spiral-bound wrappers. Lists minute-by-minute steps of the test countdown prior to the Gemini 12 launch in a column format labeled with header topics of time (T-), direction by, action by, operation, time (T-, again), and item (completed check-off column) with two sections on launch recycle procedures and emergency conditions. INSCRIBED WITH HIS MISSION TITLE BY BUZZ ALDRIN on front cover.