"Buddha Shakyamuni's discourses which elucidate and define the principals of monastic vows and discipline is know as Vinaya Pitaka, which is one of the three primary collection of discourses which comprises in the Buddhist Canon.
Based on the different interpretations relating to the subtler points of Buddha's discourses on Vinaya there emerge several distinct Vinaya schools in India. However, the Vinaya tradition, which became predominant in Tibet is that of the Sarvastivada School.
Vinaya literally means "discipline", the term generally refers to monastic discipline and especially to observance of the ethical codes which regulate the life of an ordained monk or nun.
For the individual Buddhist monks or nuns, spiritual discipline means the nurturing of mental awareness that leads to control of one's response to the phenomenal world of conditioned existence. As such, discipline is an indispensable means for the bikshu intent upon making progress toward the goal of nirvana.
The Vinaya Pitaka defines a means by which an individual monastic adherent may achieve the soteriological goal of Buddhism and it determines the manner in which the collective community may sustain its special identity.
In order to develop proper practice of Vinaya within oneself, one should first have to become monk or nun. The prime necessity for carrying out a pure Dharma in general and particularly Vinaya practice is to generate a thought of liberating every sentient being from the ocean of samsara. For that one has to uproot every discordant factors and produce its antidote, uncontaminated wisdom, which is developed only from the practice of pure morality. So therefore, one receives the monk's Pratimoksha vow, by generating a thought of renunciation and that of keeping the vows excellently.
Despite generating such indubitably excellent thought, one should cherish the vows conscientiously.
The Pratimoksha vow is divided into eight classes of individual liberation vows, which are:
1. fully ordained monks vows
2. fully ordained nun's vows
3. probationary nun's vows
4. novice monk's vows
5. novice nun's vows
6. layman vows
7. laywoman vows
8. the one day ordination vows
The procedure of observing the vows are elaborately elucidated in the Vinaya sutras.
The key to understanding the ethos of Vinaya sources involves a serious reckoning with the teaching of Buddha and the importance attached to the notion of "discipline". It will be necessary for us to reconstruct in outline from the essential elements of the Four Noble truths before we begin our consideration of Vinaya in detail."
~A talk presentation by His Eminence Aenpo Kyabgon Rinpoche during the Silver Jubilee of the prestigious Sakya College for the studies of the Highest Buddhist Philosophy in 1997 at Dehra Dun, Northern India.