The Vulcans, a humanoid race native on planet Vulcan, are one of the founding races of the United Federation of Planets. Their society is based entirely on logic and reason, any trappings of emotion are considered to be socially unacceptable.

Two thousand years ago, Vulcans where a passionate, violent people whose civilization was torn by the terrible Great Wars, in which 20 billion Vulcans were killed. After over 95% of the population had been wiped out by large scale fusion, biological, and psionic weapons, the great philosopher Surak, later revered as the father of Vulcan civilization, led his people to reject their emotions in favor of a philosophy that embraced pure logic. In this Time of Awakening, Vulcans re-established peace and understanding on their planet.

However, there was one group of Vulcans who did not accept Surak's teachings. They were banished from Vulcan and later founded the Romulan Star Empire.

In the distant past, Vulcans killed to win their mates. Even in the present, Vulcans revert to ancient mating rituals, apparently the price they must pay for totally suppressing their natural emotions. When Vulcan children are about seven, their parents select a future mate, and the two children are joined in a ceremony that links them telepathically. When the two children come of age, they are compelled to join together for the marriage rituals. The time of mating, Pon farr, is when the stoically logic Vulcans pay for their rigid control by experiencing a period of total emotional abandon. In Vulcan adults, Pon farr comes every seven years. If a Vulcan is somehow prevented from mating in the time of Pon farr, he can even die. The only alternative is a ritual fight between the concerned Vulcan and his rival, called Koon-ut-kal-if-fee ("marriage or challenge").

Because planet Vulcan has a higher gravity than Earth, and its atmosphere is thinner, Vulcans in an Earth-normal environment demonstrate greater physical strength and more acute hearing than humans. The intensity of the Vulcan sun caused the Vulcans to evolve a secondary eyelid to protect the retina This inner eyelid involuntarily closes when the eye is exposed to extremely intense light. A Vulcan's heart is were a human's liver is. When injured, Vulcans concentrate their strength, blood, and antibodies onto the injured organs in a type of self-induced hypnosis. Vulcans have telepathic capability, as practiced in the Vulcan mind-meld. The mind-melt is an ancient ritual in which to persons are telepathically linked, sharing each other's consciousness. To Vulcans, mind-melding is a deeply personal experience, providing an intense intimacy. Scientifically, the process is described as a synaptic pattern displacement.

Another ritual is the fal-tor-pan, also called the re-fusion, intended to reunite a person's katra (living spirit) to that person's body. Until 2285, the ceremony had not been performed for centuries, since in most cases a Vulcan's katra is returned home after the death of the body. However, in 2285 the fal-tor-pan was successfully used to resuscitate Spock, whose body had been regenerated at the Genesis planet following his death there in 2285.

The Vulcans, having invented spaceflight very early, were the first race to make first contact with humans in 2063. Today, they are a very and valuable member of the United Federation of Planets. The Vulcan Science Academy located in Vulcan's capital Shari'Kahr is one of the Federation's most important scientific institutes.

Vulcan is an M-Class planet located in the 40 Eridani star system. It is very hot and dry with high atmospheric pressure and relatively high gravity. Less than a fourth of the planetary surface is covered with water.

Vulcan (called T'Khasi by Vulcans) is the second planet of the system and has no moon, but a twin planet called Charon (or T'Khut, which means The Watcher) which himself has one moon. Vulcan is inhabited by 14 billion Vulcans; the capital is called Shari'Kahr. The highest mountain on the planet is Mount Seleya, on which is located an ancient temple representing a center of Vulcan religion.

The Vulcan star system, 40 Eridani (or Omicron 2 Eridani), is an interesting trinary system located at the distance of only 4.9 parsecs (=16 Lightyears) from Earth. The system consists of three stars: 40 Eridani A, B, and C. The primary star, 40 Eridani A, is an orange main-sequence dwarf of spectral type K1 V. The other two stars are both situated 400 AU from the primary star and orbit each other every 248 earth-years, at an average distance from each other of 44 AU. They together orbit 40 Eridani A every 8000 earth years. 40 Eridani B is a white dwarf of spectral type A VII. 40 Eridani C is a very faint red main-sequence dwarf of spectral type M4e V.