Here, within the constellation of Kasterborus, and in Mutter's Spiral, at galactic co-ordinates ten zero eleven zero zero by zero two from galactic zero centre on the very edge of time and space lies Gallifrey - the planet of the Time-Lords. On Gallifrey lives an immensely intelligent and highly civilized race. The Doctor's home planet is Gallifrey and is populated by a race of beings who can exist outside of time as it is ordinarily known.

The Gallifreyeans have made many extraordinary discoveries. They have opened the doors to the time barrier and unlocked the secret of travel through the Fifth Demension. It is upon that secret that the tradition of the Time-Lords has been founded, and consequently they have found themselves responsible for the policing of time travel.

Time-Lords are the aristocracy of the planet Gallifrey. The Time-Lords, while masters of science and technology, possess little common sense. Their present is more than 10 million years from the present day (figured by humans in the time scale of anno Domini).
The Time-Lords are able to monitor all the happenings and events that occur in time and space. They are trained at their respective Academies depending on their respective chapters: the Arcalians, the Patrexes, and the Prydonians.
Legends tell of the great and gifted time engineer Omega who created a super nova explosion that in time became Crab Nebulae. This gave the Gallifreyeans the power which they needed in order to develop time travel capsules called TARDIS (Time and Relative Dimensions in Space). Rassilon was the original leader of the Time-Lords. It was he who captured a black hole.
	The Black Hole

This super nova explosion is what provided the Time-Lords a constant, stable power source which they needed to perfect their researches.

It was Rassilon who created the symbols of power which were held by the President of the High Council: (1)The Matrix, a link to the APC Net (Amplified Panatropic Complex),the computer which contains the memories of all the Time- Lords who have ever lived, (2)The Sash which protects the wearer from the energies of the black hole, and (3)The Rod and The Great Key which are used in harnessing the energies of the black hole.

Gallifrey even had a great barrier erected by that original leader of the Time-Lords, Rassilon. This barrier was a means to keep other beings from interfering with the Lords of Time so that they could go about their business without coercion.

The early Time-Lords used their powers to try and help the people of the planet Minyos develop their civilization by giving them significantly advanced technology. In spite of these efforts, the Minyons succeeded in destroying each other in nuclear wars. It was at this time that the Time-Lords realized the potential harm of their discoveries. The Time-Lords made it a point to never divulge technology such as this to any other race. Laws were then instituted to govern time travel, and a non-intervention policy forbidding them from interfering in the affairs of any other culture ever again was developed. Their role was limited to that of observers, avowing only to intercede in the affairs of other cultures in the most extreme cases of injustice. As a result, Time-Lords rarely, if ever, leave their home world.

As time went on, it became apparent that these outside races would become threats to Gallifrey. The disturbed Time-Lords decided to ensure their place as masters of technology and time by creating a covert group of operatives, called the Celestial Intercention Agency (CIA). Their existence of the CIA is not known to the general populace as this existence would raise a tremendous uproar. The purpose of the CIA is to travel about time setting things "right" by altering time in ways so as not to endanger Gallifrey's present and the Time-Lord's place in the universe. Among the more prominent figures of this covert operation was the Doctor's one-time companion, Romana.

In such a rigid society the inevitable undesirable element of renegade Time-Lords arose. Throughout Gallifrey"s history there have been those who have left the planet to persue their own idealologies and ambitions because they refused to comply with the structure of Gallifrey, for good or for bad. At times these Time-Lords would steal off in TARDISes and flee Gallifrey, or attempt to subvert Gallifrey through the alteration of history. Among these renegade Time-Lords are K'Anpo, who lived on Earth as a Tibetan monk, and Drax, the builder of Mentalis, a giant computer on the planet Zeos. THE MASTER

THE MASTER

By far the most dangerous of these renegade Time-Lords is the Master. He is an avaricious, malicious, and nefarious Time-Lord whose lust for power has allied him with some of the most evil and ruthless elements in all the universe. He is an extraordinary hypnotist with a particular trademark of murder. His favorite weapon is the compression gun which leaves his victims' atoms in doll-sized corpses.

Time-Lords are also powerful telepaths. Within their genetic tree, Time-Lords have four telepathic Persuasions: Active - which imposess a Time-Lord's will upon another; Passive - which allows a Time-Lord a sense of those around him; Empathic - which allows a Time-Lord sway over another's emotions; and Uncertain - which is a blend of the other three at a lower power. In their own way, all four Persuasions are tremendously powerful, advancing the Time-Lord to the point of being able to vacate their own bodies in one way or another. The great Rassilon was able to eventually achieve this feat.

Like all Gallifreyans, the Doctor's physiology is quite unique and different from that of the human. He possesses a redundant cardiovascular system which consists of two hearts, a respiratory bypass system, and a body temperature of 60 degrees farenheight. All Gallifreyans are naturally long-lived compared to humans, and are usually able to easily reach a lifespan of more than 600 years.

The Doctor's Chest X-Ray showing His 2 Hearts

Gallifreyans have a unique endowment, the ability to regenerate their bodies, to prevent premature death. This is the ability of Total Cellular Regeneration, thus Time-Lords do not experience death as humans know it. When the body of a Time-Lord nears death, a self-replicating swarm of nanotech machines (cell-sized robots) sets about repairing, restoring, and reorganizing the cells of their host-body. This results in a completely new body and physical appearance for the formerly near death Time-Lord, and often a radical change in personality.

Some Time-Lords (Such as K'Ampo, and Romana) can exert willful control over the regenerative process, and thus control the nature of the new body's form. The Doctor, in contrast, has displayed time and again the symptoms of "problem regeneration." It always seemed to be something of a struggle for him, both in the physical and psychological sense. In fact on 3 separate occasions the Doctor would not have survived had the regeneration not been pushed by outside forces (The Doctor's first regeneration was assisted by the TARDIS itself. The 3rd had to be activated by the Gallifreyan K'Ampo, and the 4th was facilitated by the Watcher, a mysterious future projection of the Doctor himself.). This may be due, in part, to the Doctor's rumored Half-Human heritage.

Thus far, the Doctor has regenerated 8 times, resulting in 9 different incarnations. Every Time-Lord is able to regenerate 12 times. However, note that it has been suggested (mainly by the Doctor himself, during his 7th incarnation) that the Doctor may be more than a Time-Lord, in that he possesses powers and knowledge far beyond those of the average Time-Lord. While there is some evidence to support this claim, there is not enough to prove the assertion.