Hinduism

The origins of Hinduism can be traced to the Indus Valley civilization sometime between 4000 and 2500 BCE. Though believed by many to be a polytheistic religion, the basis of Hinduism is the belief in the unity of everything. This totality is called Brahman. The purpose of life is to realize that we are part of God and by doing so we can leave this plane of existance and rejoin with God. This enlightenment can only be achieved by going through cycles of birth, life and death known as samsara. One's progress towards enlightenment is measured by his karma. This is the accumulation of all one's good and bad deeds and this determines the person's next reincarnation. Selfless acts and thoughts as well as devotion to God help one to be reborn at a higher level. Bad acts and thoughts will cause one to be born at a lower level, as a person or even an animal. 

Hindus follow a strict caste system which determines the standing of each person. The caste one is born into is the result of the karma from their previous life. Only members of the highest caste, the brahmins, may perform the Hindu religious rituals and hold positions of authority within the temples.

Classifying the many groups within Hinduism is a challenge, and not so easy (as, perhaps, with other religions.) In so doing, we may inadvertently promote the idea that Hinduism is a single monolithic religion. It is, more accurately, a family of religions, with each family member autonomous but sharing distinctive family features.

In discussing all religious groups, we may imply that they are static, homogeneous and well-defined "wholes." In actual fact, they are fluid and evolving traditions, internally diverse and contested, and hazy at the edges. In trying to discern specific strands within Hinduism, therefore, we are also in danger of over-generalising, promoting stereotypes and creating false boundaries. Nonetheless, it is useful – even necessary – to establish a somewhat tentative framework for categorising the numerous groups and sub-groups. Here we categorise them according to three criteria:

1. focus of worship
2. doctrine
3. preferred process or practices

Four main communities can be identified, each according to its respective focus of worship (these four communities are discussed in the Vaishnavism, Shaivism, Shaktism, and Smarta pages). Each community, which we loosely term here a "denomination," favours its own specific deity or deities.

1. Vaishnavas worship Vishnu (usually as Krishna or Rama)

2. Shaivas worship Shiva (often in the form of the linga)

3. Shaktas worship Shakti, also known as Devi (especially Parvati, Durga, Kali)

4. Smartas worship five deities i.e. Vishnu, Shiva, Devi, Ganesh, and Surya

In the UK many individuals and temples will not specifically align themselves to one (or more) of these traditions. They worship deities from all these traditions. They often describe themselves as "Sanatanist" to reflect their more inclusive nature. Underpinning them, there is often a leaning towards the monistic Smarta conclusions of Shankara.

Shaivism and Shaktism are often closely related, especially within tantric traditions, which explore the male-female symbolism of Shiva-Shakti.

• Vaishnavas are mostly personalists and favour the path of bhakti-yoga.
• Shaivas are often impersonalists with tendencies towards jnana- and astanga­yoga (closely linked to sankhya-yoga). There are, however, notable personalistic, bhakti strands, especially in South India (e.g. the Lingayats).
• Shaktas tend to be impersonalists, and their worship often focusses on material benefit (karma-yoga). Their theology tends to be less developed and draws largely on Shaivism.
• Smartas follow the impersonal (advaita) doctrine of Shankara and favour the path of jnana, featuring renunciation and philosophical inquiry. 

source: hinduism.iskcon.org/tradition/1200.htm