Spock, (aka Mr. Spock), is a main character in the original Star Trek TV series and one of the most enduring characters from American 1960s television. He is one of the only aliens in the permanent cast: half-Vulcan, half-Human, and serves as the science officer and first officer of the USS Enterprise, under Captain James T. Kirk.
His personal struggle between the Vulcan logical self and his human emotional self is the centerpiece of the character and created some evocative drama. He was originally portrayed by actor Leonard Nimoy (except for brief scenes of a much younger Spock in two later movies) and is currently being portrayed by both actor Zachary Quinto and Nimoy.