CASTRO, Fidel (1927-2016). Autograph letter signed ("Fidel"), in Spanish, to an unnamed recipient. N.p., n.d. [c.1962]. 1 page, 4to, on Secretaria de Organizacion, C.T.C. Revolucionara letterhead, lightly creased at fold. Castro urgently requesting specific information about the height above sea level of a particular area and the fluctuation due to its changing tides: "I need to know the height of the land above sea level in that area, and the fluctuation of the sea with complete exactitude. You will do me a great favor if you get the people to do it. Give them everything they need as soon as possible, and tell them mot to make any mistake in this undertaking. Fidel." Rare. [With:] 5 x 8 in. photograph of Fidel Castro signing an autograph for a Vietnamese student, captioned on verso: "13A Hungria 1972."