Originally vulcans was a violent and emotionally unstable species but as time passed and they started developing new technology they realized that if things were to continue as they do their violent nature would not only threaten the extinction of other species but potentially themselves as well.
And so a Vulcan named Surak developed a philosophy that would help all Vulcans purge their emotions and embrace logic, making the Vulcan race into what we know today - a collective of emotionless and highly logical people, it is worth noting however that not all Vulcans embraced this philosophy and some ended up leaving Vulcan and settle elsewhere, the most well known of these groups settled on Romulus and became the Romulan Empire.
As anyone who have known a Vulcan well can attest to however, while Vulcans might say that they do not have emotions - the fact is that their emotions are still there and as strong as ever, they are merely suppressed.
When Zefram Cochrane first left earth in humanity's first ever warp capable ship they caught the attention of a passing alien vessel, that vessel was vulcan. Realizing that humanity was becoming a warp capable species the vulcans decided to proceed and make first contact with humanity - they were the first race to ever do so and they found humanity still struggling to recover from the massive devastation and poverty brought on by World War III - with humanity reminding the vulcans of themselves in times passed with their unstable emotions they took pity on humanity and decided to take them under their wing, and help guide them for what lies ahead, curing poverty and disease in the process.
It would end up taking a lot longer then expected however but after more then a century humanity finally struck out on their own, exploring space in their first real warp 5 starship despite the Vulcan protests claiming that humanity was not yet ready.
Humanity would end up surprising the Vulcan race however and eventually humans and Vulcans together with andorians and tellarites would found the Federation Of Planets, a vast alliance of races that would eventually become one of the major powers in the entire galaxy.
The vulcan race was created by Gene Roddenberry, he created the half-human/half-vulcan character Spock to appear in the original Star Trek TV show.
On the outside vulcans look much like humans but with a few distinguished differences, most notably their pointed ears. Vulcans tend to stay well groomed - they rarely let their facial hair grow although they are able to do so should they wish, almost all vulcans have short black hair that they cut in a efficient and plain manner as well as arched thick eyebrows, giving them a stern look.
On the inside humans and vulcans look very different but are surprisingly similar genetically, humans and vulcans can easily have children together. One notable difference is that vulcans blood are green which can also give their skin a very slight green tint.
After maturity vulcans will start to experience a primal mating instinct every 7 years called the Pon Farr, not mating during this time can possibly result in serious injury or even death. During the Pon Farr most vulcans loose their emotional control.
Powers and Abilities
Strength: A vulcan have about three times the strength of a human, making their strength much superior to humans.
Intelligence: Most vulcans demonstrate some degree of superior intelligence, commonly in ways such as solving complex calculations using only their mind, or stating the exact amount of time that has passed from a certain moment down to the seconds.
Senses: Vulcans possess an increased sense of hearing, only the women possesses an increased sense of smell as well.
Reflexes: Vulcans possess superior reflexes to that of a human.
Respitory Systems: Having evolved on a planet with a much thinner atmosphere vulcans can survive much easier then humans in low oxygen environments.
Heat Tolerance: Having evolved on a very hot and dry planet, vulcans have an increased tolerance to heat. However older vulcans can become sensitive to lower temperatures.
Nutritional Needs: As another bi-effect of growing up in a harsh climate vulcans can survive several days without food or water.
Sleep: Vulcans can function without sleep for two weeks.
Metabolism: Vulcans have a superior metabolism, they are barely affected by the effects of things such as caffeine.
Longevity: A vulcan can live up to 200 years, sometimes ever more.
Vulcan Nerve-Pinch: A technique commonly only used by vulcans, it allows them to use one hand to put pressure slightly beneath the shoulder of a person and rendering them unconscious nearly instantly. It has proven effective on most humanoids with a few rare exceptions.
Telepathy: All vulcans possess some degree of telepathy which is commonly used to perform mindmelds, a melding of minds that allow the sharing of thoughts and feelings. Vulcans have also been shown to affect the emotional states of people nearby and make other types of telepathic "suggestions".
The Original Series is where the vulcan race first appeared, the show featured the half human/half vulcan Spock as one of the main character.
While vulcans make several appearances over the duration of the series none of the main characters are vulcan.
Like in The Next Generation several vulcans are featured, although none of the main characters are of vulcan descent.
Voyager features the vulcan tactical officer Tuvok as one of the main character of the show.
As a prequel the show often showcases the early relationship between the human and vulcan species. The Enterprise first officer and one of the main characters of the show is a vulcan named T'Pol.
The Animated Series features a few appearances by vulcan characters, including Spock.
The following films features appearances by vulcans either as a main character or as side characters.
The list of video games as well as a variety of board games and card games set in the star trek universe is quite extensive, most of them feature vulcans to some degree. You can find a list of Star Trek video games here.