[MANHATTAN PROJECT]. [GROVES, Lt. General Leslie R. (1896-1970), subject]. Invitation to Groves, Director of the Manhattan Project, to Join ?The Military Order of the World Wars.? New York: Military Order of the World Wars, ca. 1940s-1950s]. Folded folio sheet, printed on recto and verso. Approximately 510 x 201 mm unfolded. Front of recto signed and inscribed ?Lieutenant General Leslie R. Groves? by Commander Charles Hann, Past Commander-in-Chief. Light rubbing, creasing, recto toned. An invitation to join a respected military organization to Lt. General Groves, the Army Corps of Engineers officer who oversaw the construction of The Pentagon, and was the director of The Manhattan Project.