This poster commemorates the 4th Planetary Congress of the Association of Space Explorers (ASE). The Congress took place October 3-7, 1988 in Sofia, Bulgaria. Bearing the authentic and original signatures of thirty-nine of the participating astronauts from eleven nations, it is part of a series of limited Collector’s Edition posters that have been produced and signed at each ASE Congress since the Association was founded in 1985. One hundred and twelve posters were signed at the 4th Congress. The poster has two headings, the main heading in English at the top, with the Russian displayed at the bottom. Around the periphery are printed translations of "Association of Space Explorers" in the native languages of all individuals who have flown in space. Clockwise, from upper left with English at the top, they include Bulgarian, Vietnamese, Mongolian, French, Polish, Romanian, Dutch, Czech, German, Arabic, Italian and Hungarian. The background is taken from NASA archive photo # 83 HC 213 which has been used for each set of posters in the series. The central image of the poster was specially rendered for this Congress by Soviet cosmonaut and artist Vladimir Dzhanibekov and features a cratered planetary surface with a shield bearing the name MARS resting upon a broken sword. Piercing the shield is a spear adorned with a white flag waving in the wind above. In the distant sky a colony orbits the planet circled by a fan of flags representing Earth's nations. The image represents the Congress theme "Space and Evolution" and reflects the development of human civilization from primitive and warlike to that of a civilization engaged in the peaceful, cooperative exploration of space. # in series: 112 Signature key included