SETI – SCHWARTZ, Robert N. & TOWNES, Charles H. “Interstellar and Interplanetary Communication by Optical Masers.” Washington, D.C.: Institute for Defense Analyses, February 27, 1961.

The founding work of optical SETI (Search for Extra Terrestrial Intelligence). A very rare advance copy, dated more than a month before the article’s publication in Nature.

“The classic paper published in Nature that started it all” (coseti.org). For years, SETI’s research had focused on radio signals, but these authors were the first to propose that “we are now not very far from the development of maser oscillators and other appropriate apparatus in or near the optical region which will allow detectable light signals to be beamed between planets of two stars separated by a number of light years” (p. 1). Charles Townes was one of the first builders of masers (a term which he coined in 1953), work for which he was awarded the Nobel Prize in 1964. His and Schwartz’s idea that masers and lasers could be employed in the search of extra-terrestrial intelligent life was way ahead of its time. Their alternative scheme of using mirror and lens telescopes to look for flashing lights (optical SETI) was not acted on until the 1990s.

Quarto. 14 pages, rectos only. Mimeographed, stapled (page edges a little browned). Provenance: David Katcher, founding editor of Physics Today, d. 2003 (ownership inscription “Mr. Katcher” at the top of the first page).