The first aliens to make contact with Earth when Zefram Cochrane made the first warp flight, the Vulcan's have evolved to suppress emotions and work purly on logic. They also experience the Ponthar, an intense desire to mate, every 7 years.
Many Vulcans have served on Starfleet vessels. On the Enterprise NX-01, T'Pol served under Captain Archer in the series Enterprise. Spock was Captain Kirk's first officer and Tuvok was Voyagers head of security.