The Vulcan salute is a hand gesture consisting of a raised hand, palm forward with the fingers parted between the middle and ring finger, and the thumb extended. Often, the famous line "live long and prosper" was briefly said after it. The salute was devised and popularised by Leonard Nimoy, who portrayed the half-Vulcan character Mr.
Spock on the original Star Trek television series in the late 1960s. 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 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 manual dexterity as individuals finding the gesture elementary to perform are less likely to report this fact than those finding the gesture difficult to make. 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. In his autobiography I Am Not Spock, Nimoy wrote that he based it on the Priestly Blessing performed by Jewish Kohanim 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)", and has a superb significance in Judaism. 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.