Master Countdown, [Gemini] Launch Vehicle, SLD, GLV-12. Martin Co., 10 October 1966. 8.5 x 11 in. with a spiral binding Lists minute-by-minute steps of the test countdown prior to the actual Gemini 12 launch. Includes two sections on launch recycle procedures and emergency conditions. INSCRIBED WITH MISSION TITLE AND SIGNED BY BUZZ ALDRIN on front cover.