Introduction
            Scholars are skeptical  that the earlier Sutras contain exactly the real teachings of Siddhartha Goutama. However, different traditions report the Four Noble Truths,  which allegedly has been preached by the Buddha right after his  enlightenment, with little discrepancies. And in fact these doctrines  represent the kernel of the Buddhism's teaching that every subsequent  traditions has dealt with.
            Sacred texts and other main texts: the Sutras.
            A Sutra is a sacred text of Buddhism said to contain the discourses of the Buddha as heard by his disciples. Apart from Sutra, Buddhist texts can also be classified as Vinaya, (monastic regulations) or Shastra, doctrinal treatises.
            Acknowledged authority: the Incipit of a Sutra
            Every Sutra,  regardless of the origin, language, or date of production, starts with  the phrase: "Thus I have heard". The Buddhist tradition holds that  Ananda, the beloved disciples of Buddha, memorized each discourses, so  that when time came to put them down in written form, he started his  recitation with the phrase "thus I have heard (from the Master)". This  is the traditional phrase that sanctions the authority of a Buddhist  text as a Sutra, and it is found also in texts obviously postdating the death of Buddha. 
            Main doctrinal tenets: Four Noble truths, Eightfold path, Enlightenment and Nirvana
            See Analysis and Comment ofDhammacakkappavattana Sutta
            
            Sources' Analysis and comment
             Source 1. Dhammacakkappavattana Sutta
            Glossary
            Blessed One: the most used epithet of Buddha. 
            One Attuned to Reality: Other epithet of Buddha.
            Five bundles of grasping-fuel: the five psycho-physical constituent of the individual. 
            This Sutra contains the followings pivotal teachings of Buddhism:
            1) The Middle Way
            As the first and second  paragraphs explain, Buddhism rejects the extremities of luxurious  self-indulgence and inhuman self-mortification. In other words, being  completely absorbed into the pleasures of this world, or alternatively  being disgusted and willing to put an end to one's own mundane  existence, are both wrong paths that will not lead to liberation.
            2) The Four holy truth
            These are explained in paragraph 3, 4 and 5. The First Truth enlightens one omnipresent aspect of existence: suffering. In the  Buddhist view, suffering has three aspects: a)The obvious physical and  mental suffering associated with birth, aging, illness and dying. b)The  anxiety of trying to hold on to things we love, as well as the distress  of being in contact with things we hate. c)A basic unsatisfactoriness  pervading all forms of existence, due to the fact that all forms of life  are changing. 
            The Second Truth explains the origin of this suffering, that is, craving. Moved by desire towards things, human beings suffer, produce Karman and continue to be reborn in the Samsara (the cycle of Rebirth). Craving is not only directed towards positive  things, like the sense-pleasures, or the mere desire to live, but it is  understood also as a craving for destruction of things we dislike,  includeding one's own life. These two opposite attitudes, attachment  towards things we like, and aversion towards things we dislike, are  linked to the concept of Middle Way exposed above. Attachment and aversion are the two fires (or poisons) that fuel suffering and bad Karman.
            After having identified the origin of suffering, the Third Truth affirms that suffering can cease once suppressed his cause, namely, craving.
            The Fourth and last Truth explains the method for the cessation of suffering, the Noble Eightfold Path.
            3) Impermanence
            The First Truth,  explaining the nature of suffering, has an important implication:  everything is subject to change and decay. Everything human beings try  to hold on to forever, will inevitably pass away.  In sum, one of the  pivotal principle in Buddhism is that the true nature of every phenomena is impermanence.  In the Buddhist view, nothing has a permanent nature.  The ignorance of  this fact is the third fire (or poison)  that fuel suffering and bad Karman.
            4) The Noble Eightfold Path
            It summarize the way leading to  the cessation of suffering  and the achievement of enlightenment. It is  used to develop insight into the true nature of phenomena  and to  eradicate attachments towards the world. It's steps can be divided in  three basic divisions:
            Wisdom           
            1. Right view: a thoroughout  understanding of the impermanent nature of  phenomena and of the origin and cessation of suffering.
            2. Right resolve: a persistent commitment towards liberation.
            Ethical conduct            
            3. Right speech: abstaining from lying, divisive speech, abusive speech, and  idle chatter.        
            4. Right action: Abstaining from taking life, from stealing, and from illicit sex.
            5. Right livelihood: abstaining from occupation that harms or exploits others, or earning more than one needs.           
            Meditative practice
            6. Right effort: a persisting  effort to abandon all those thoughts, words, and deeds that hinder the  path towards liberation.        
            7. Right mindfulness:  being aware of one's thoughts, feelings, and actions so that one is not controlled by them.        
            8.Right mental unification: the right methods of meditation.
            5) Enlightenment and Nirvana
            These two terms are strictly connected. Enlightenment means attaining the same experience and understanding of the nature of things as Buddha did. As a consequence of Enlightenment, Nirvana is attained. The term Nirvana literally means "extinguishing", namely the extinction of the  aforementioned three fires of attachment, aversion and ignorance. When  these fires are extinguished, suffering comes to end and Karman is no longer produced. Nirvana is then the goal of Buddhism, but it does not represent some sort of Absolute.
            Source 2. Dharma wheel
            A simple image of the Dharmachakra, the Wheel of the Law.  It is recognized as the foremost symbol of Buddhism. Its roundness  symbolizes the perfection of the Buddha's teaching, while the number of  its spokes varies, with different meanings for each number. The most  common version has eight spokes, symbolizing the Noble Eightfold Path.
            To go Deeper
            This link leads to a web page  where the arguments presented in this page and in section 3 are  explained in a interactive Image of a Wheel of Life. Other more-in  depth-arguments are also provided.
            http://languagecenter.emory.edu/languages/tibetan_samsara/
            Intercultural and interdisciplinary information
            (Other Modules, History of Philosophy)
            1) Buddhism and Hinduism share a similar ideal of liberation, the liberation from Samsara. However, the Buddhist vision of Impermanence represents an important difference between Hinduism and Buddhism. For  Hinduism there is a permanent Absolute behind a constantly changing  world, the Brahman, and its equivalent in each human being, the Atman. In the Hinduist view, by awakening to this pristine union, man is liberated from Samsara.  By Contrast, for Buddhism, these two principles have been rejected as  two deceptive illusions of something permanent that hinder the way  towards enlightenment.
            See link to Hinduism's Module
            2) In the early days of the  study on Buddhism, many Western scholars were fascinated by rational  outlook of the first Buddhist texts.
            Buddhism drew the attention of  European intellectuals for the first time during the course of the  nineteenth century through the work of Christian missionaries, scholars  and officials of the British Empire.
            Among the first to take an  interest in Buddhist thought  was Arthur Schopenhauer. In his major  work, "The World as Will and Representation" (1819) are found several  similarities with the preaching of the Buddha, such as  the omnipresence  of pain in the lives of all beings or the identification of the "will"  (which could be equivalent to the Buddhist 'attachment ') as the primary  cause of suffering. 
            Also Friedrich Nietzsche openly praised this religion in his work Antichrist (1895), aphorism 20: 
            "Buddhism is a hundred  times as realistic as Christianity -it is part of its living heritage  that it is able to face problems objectively and coolly; it is the  product of long centuries of philosophical speculation. The concept,  "god," was already disposed of before it appeared. Buddhism is the only  genuinely -positive- religion to be encountered in history, and this applies even to its epistemology (which is a strict phenomenalism)"
            However, it should be noted  that this extremely rationalistic interpretation of Buddhism was  influenced by the intellectual milieu of the nineteenth century:  rationalistic and often critical of Christianity. This has often  hindered a full understanding of Buddhist traditions in their more  devotional and ritual aspects (see for example sections 9 and 10).
            Nonetheless, it is undeniable that  Buddhism offers a long tradition of profound philosophical speculation,  which increasingly draws the interest of contemporary scholars of  philosophy. 
            Link to other modules:
            Hinduism's Module, section 3