The Four Noble Truths are taught in Buddhism as the fundamental insight or enlightenment of Sakyamuni Buddha (the historical Buddha), which led to the formulation of the Buddhist philosophy.

1. Dukkha: All worldly life is unsatisfactory, disjointed, suffering.

2. Samudaya: There is a cause of suffering, which is attachment or desire (tanha).

3. Nirodha: There is a way out of suffering, which is to eliminate attachment and desire.

4. Marga: The path that leads out of suffering is called the Noble Eightfold Path.

This outline form is exactly that used by doctors of the Buddha's culture when diagnosing and prescribing for a disease: identify the disease, its cause, whether it is curable, and the prescribed cure. Thus the Buddha treats suffering as a "disease" we can confidently expect to cure.

Because of its focus on suffering, Buddhism is often called pessimistic. But since Gautama Buddha presented a cure, Buddhists consider it neither pessimistic nor optimistic but realistic.

The Noble Eightfold Path, according to Buddhism and as taught by Gautama Buddha, is the way to the cessation of suffering, the fourth part of the Four Noble Truths. It is summarized into three important categories: wisdom, virtue, and concentration.

The following is An Analysis of the Path, a sutra or discourse delivered by Gautama Buddha, who uses the word "right" (samm) to carry the sense of "perfect" or "ideal".

Wisdom  (pañña)

1. Right Understanding (or Right View, or Right Perspective)
"And what, monks, is right understanding? Knowledge with regard to stress, knowledge with regard to the origination of stress, knowledge with regard to the stopping of stress, knowledge with regard to the way of practice leading to the stopping of stress: This, monks, is called right understanding.

2. Right Thought (or Right Intention, or Right Resolve)
"And what is right thought? Being resolved on renunciation, on freedom from ill will, on harmlessness: This is called right thought.

Virtue  (sila)

3. Right Speech
"And what is right speech? Abstaining from lying, abstaining from divisive speech, abstaining from abusive speech, abstaining from idle chatter: This, monks, is called right speech.

4. Right Action
"And what, monks, is right action? Abstaining from taking life, abstaining from stealing, abstaining from unchastity: This, monks, is called right action.

5. Right Livelihood
"And what, monks, is right livelihood? There is the case where a disciple of the noble ones, having abandoned dishonest livelihood, keeps his life going with right livelihood: This, monks, is called right livelihood.

Concentration  (samadhi)

6. Right Effort (or Right Endeavour)
"And what, monks, is right effort?
(i) There is the case where a monk generates desire, endeavors, activates persistence, upholds & exerts his intent for the sake of the non-arising of evil, unskillful qualities that have not yet arisen.
(ii) He generates desire, endeavors, activates persistence, upholds & exerts his intent for the sake of the abandonment of evil, unskillful qualities that have arisen.
(iii) He generates desire, endeavors, activates persistence, upholds & exerts his intent for the sake of the arising of skillful qualities that have not yet arisen.
(iv) He generates desire, endeavors, activates persistence, upholds & exerts his intent for the maintenance, non-confusion, increase, plenitude, development, & culmination of skillful qualities that have arisen: This, monks, is called right effort.

7. Right Mindfulness
"And what, monks, is right mindfulness?
(i) There is the case where a monk remains focused on the body in & of itself -- ardent, aware, & mindful -- putting away greed & distress with reference to the world.
(ii) He remains focused on feelings in & of themselves -- ardent, aware, & mindful -- putting away greed & distress with reference to the world.
(iii) He remains focused on the mind in & of itself -- ardent, aware, & mindful -- putting away greed & distress with reference to the world.
(iv) He remains focused on mental qualities in & of themselves -- ardent, aware, & mindful -- putting away greed & distress with reference to the world. This, monks, is called right mindfulness.

8. Right Concentration
"And what, monks, is right concentration?
(i) There is the case where a monk -- quite withdrawn from sensuality, withdrawn from unskillful (mental) qualities -- enters & remains in the first jhana: rapture & pleasure born from withdrawal, accompanied by directed thought & evaluation.
(ii) With the stilling of directed thought & evaluation, he enters & remains in the second jhana: rapture & pleasure born of concentration, one-pointedness of awareness free from directed thought & evaluation -- internal assurance.
(iii) With the fading of rapture, he remains in equanimity, mindful & fully aware, and physically sensitive of pleasure. He enters & remains in the third jhana, of which the Noble Ones declare, 'Equanimous & mindful, he has a pleasurable abiding.'
(iv) With the abandoning of pleasure & pain -- as with the earlier disappearance of elation & distress -- he enters & remains in the fourth jhana: purity of equanimity & mindfulness, neither pleasure nor pain. This, monks, is called right concentration."