This set of uncut 18 cent US stamps also come in a booklet that has interesting space and space exploration facts. Envelope is approx 11" x 9". Booklet and stamps are all in good, unused condition with no known damage. This block of eight stamps was issued to celebrate the great achievements made by man in the field of space exploration. The individual stamps recall great moments that occurred during the United States crusade into the unknown. Those highlights include the walk on the moon and the development of the Columbia space shuttle and Skylab. These issues also honor the advancement of telescopes and satellites, which allow us to study the planets and communicate with countries around the globe.