This is a large lot of more than 75 authentic NASA Lithographs plus another 10 not labeled NASA. There are 3 sets that have an intro page. They are Exploring Earth From Space, Microgravity Science Research Space Shuttle Missions, and Mars Pathfinder. Not all the Lithographs are in them and there a few duplicates. There are individual ones of astronauts, flight crews, missions etc. There may be quite a few valuable ones in this lot. Don't really know values and just want to sell the lithographs all together.