The Vulcan salute first appeared in 1967 on the Star Trek second season opening episode, "Amok Time". The gesture famously has a reputation for being difficult for some people to make without practice or the covert pre-positioning of the fingers, and actors on the original show reportedly had to position their fingers off-screen with the other hand before raising their hand into frame. This reputation may stem from variations in individuals' manual dexterity. This reputation is parodied somewhat in the motion picture Star Trek: First Contact when Zefram Cochrane, upon meeting a Vulcan for the first time in human history, is unable to return the Vulcan salute gesture and instead shakes the Vulcan's hand.
Blessing gesture that was the inspiration for the Vulcan salute
In his autobiography I Am Not Spock, Nimoy wrote that he based it on the Priestly Blessing performed by JewishKohanim with both hands, thumb to thumb in this same position, representing the Hebrew letter Shin (ש), which has three upward strokes similar to the position of the thumb and fingers in the salute. The letter Shin here stands for Shaddai, meaning "Almighty (God)". Nimoy wrote that when he was a child, his grandfather took him to an Orthodox synagogue. There he saw the blessing performed and was very impressed by it.
The accompanying spoken blessing, "live long and prosper", ("dif tor heh smusma" in the Vulcan language as spoken in Star Trek: The Motion Picture) also appeared for the first time in "Amok Time", scripted by Theodore Sturgeon. The less-known reply is "peace and long life", though it is sometimes said first, with "live long and prosper" as the reply. This format is similar to common Middle Eastern greetings (Salaam alaykum in Arabic and Shalom aleichem in Hebrew), meaning "peace be upon you", and its reply, "upon you be peace". An even more ancient variation can be found with the Ancient Egyptians: the blessing "ankh wedja seneb", usually translated as "may he live, be prosperous, be healthy."William Shakespeare's Romeo and Juliet contains the line, "Live and be prosperous: and farewell good fellow." The phrase 'live long' first appeared in print in 1957 in Eric Frank Russell's science fiction classic 'Wasp' where it was used both as a greeting and as a farewell by Earth's deadly enemies, the Sirians.
^The exact translation of the Egyptian hieroglyphics phrase into English is somewhat open to interpretation, however "life", "prosperity" and "health" are the three symbols used in the formula. The Something Awful comedy website article "Hieroglyphs Are Sweet" translates it as "Live long".., while the more academic source (Gardiner, Alan (1957). Egyptian Grammar. Griffith Institute, Ashmolean Museum, p. 239) gives it as "may he live, be prosperous, be healthy."
The Jewish Origin of the Vulcan Salute – a page by Rabbi Yonassan Gershom, with photos and diagrams of how the Salute forms the Hebrew letter Shin, the use of the Blessing Hands gesture on Jewish gravestones and jewelry, etc.