The term "Neopagan" is used by academics and adherents alike to denote those Pagan traditions which are largely modern in origin, or which are conceived as reconstructions of ancient practices.

What is it?
Neopaganism is a "post-Christian" new religious movement with roots in early 19th century Romanticism.
Beliefs and practices are diverse. Some Neopagans tend to meld various religious practices, folk customs and ritual techniques. Others observe a specific ancient religion Still other Neopagans practice a spirituality entirely modern in origin.

Followers
In the USA, Wicca is the largest Neopagan movement revering nature and active ecology, a Goddess, use of ancient mythologies, the belief in magic and often the belief in reincarnation. In some cases, notably in Icelandic Asatru, the revivalist movements may blend with surviving strains of pre-Christianization folklore.
According to estimates there are in a strict sense more than 1mio Neopagans followers worlwide. It is particularly popular among young people with women representing 75% of followers.

God
For most Neopagans only a single female divine being exists, a life force of the universe, who is immanent in the world. Various used names and archetypes are seen not as separate entities, but as facets of something that is far beyond our abilities to see, know, or understand.

Some are pantheist, believing that all existence/the universe is Deity, or panentheist believing that the Goddess interpenetrates all of nature but has also distinct identity;

For Wiccans, divinity is bipolar as two bodies dominate: Goddess and God, with many lesser aspects. But the Goddess represents matter while the God represents time. Time without matter is not possible, thus the Goddess is the stronger one.

For reconstructionist Pagans, (Nordics, Celtics, Near East Reconstructionists, Greeks, and some Druids), divinity is polytheistic.

For some Druids and High Magicians there is an overall One but other divinities are also recognised.

History
During Christianization, Christianity became itself suffused by pagan elements, but it was not until the High Middle Ages that interest of the scholastic in the culture and religion of Classical Antiquity began to revive. Thomas Aquinas attempted to fuse concepts of Graeco -Roman philosophy and cosmology with Christianity. During the Renaissance, Graeco-Roman mythology became omnipresent in Europe clad in Christian inter pretation.

Neopaganism as such began with 18th century Romanticism, and the surge of interest in Germanic paganism with the Viking revival in Britain and Scandinavia. Neo-Druidism was established in Britain since 1792 and may qualify as the first real Neopaganism. Germany was reached in the late 19th century.

The 1960s and 1970s saw the rise of Germanic Neopaganism, Ásatrú in Iceland and Odinism in the USA.

Many Neopagans and Neopagan traditions attempt to incorporate historical religions and mythologies into their beliefs and practices, emphasizing the age of their sources. Wicca in particular is sometimes referred to as the "Old Religion" This is not particular to Neopaganism but is found in many other “standard” religions as well. The mythological sources of Neopaganism include Celtic, Norse, Greek, Roman, Sumerian, Egyptian and others.

Beliefs
Some groups focus on one tradition; others draw from several and some Neopagans also draw inspiration from Christianity, Buddhism and others. Since most Neopaganism does not demand exclusivity, Neopagans can practice other faiths in parallel.

Neopaganism generally emphasizes the sanctity of Earth and Nature. Some Neopagans are influenced by Animist traditions of Native Americans and Africans. Neopagans often feel a duty to protect the Earth through activism, and support causes such as rainforest protection, Organic farming, permaculture, animal rights, etc.

Most Neopagan traditions are polytheistic, but the interpretation of the concept of deity may vary widely, including pantheistic, deist, henotheistic, psychological and mystical interpretations.

In Wicca, the concept of an Earth or Mother Goddess is emphasized, but male counterparts are also evoked.

Many Neopagan movements overlap with occultism, witchcraft and magic. Wicca in particular emphasizes the role of witchcraft and ritual.

Most Neopagan religions celebrate the cycles and seasons of nature through a festival calendar that honors these changes. The festival calendar can change from climate to climate, and can also depend upon one's religious path of choice.

Worship
Most Neopagans do not have distinct temples, usually holding rituals in private homes or sacred groves. Many adherents keep their faith secret for fear of repercussions. and work within no fixed spiritual community.

Main Branches of Neo Paganism
While reconstructionism, is an attempt to base a modern approach to paganism on a particular historical culture, syncretistic or eclectic approaches adopt various historical influences and synthesize them into a personalized religion.

Reconstructionist
Main stream combines Hellenistic and Roman traditional beliefs. They argue that Greek and Roman religions would have been difficult to disentangle from each other, even in late antiquity, due to cultural exchanges and diffusion of cults and philosophies during the Roman empire.
Some of the Hard Reconstructionists seem to view this practice with some disdain In the US Greek Paganism is often called Hellenismos, and Roman Paganism often is known as the Religio Romana.

Celtic
Inspired by the cultures of Ireland, Scotland, Wales, Cornwall and Brittany and Greek and Roman records of Druidry. Some present-day Druids attempt to reconstruct the beliefs and practices of ancient Druidism. Other modern-day followers of Druidism claim to have worked directly with the spirits of places, of pagan gods and of their own ancestors to create a new Druidism

Slavic
Most Slavic neopagans follow customs of old Slavic religion and revere Slavic gods.As a group these Slavic religions are known as Slavianstvo. Most Slavianstvo call themselves heathens rather than pagans. While some Slavic neo-pagan groups are reconstructionist some especially in urban areas in Russia and Ukraine, are marked by nationalism.

Wicca
traces back in the UK to the late 1940s. Wicca is based on the symbols, seasonal days of celebration, beliefs and deities of a variety of ancient cultures, including Celtic and Germanic. Added to this material are heavy Masonic and ceremonial magical components from recent centuries.
Since Wicca is so flexible and syncretic (some call themselves Christian Wiccan) it could be considered a New Age spirituality. The main branches of Wicca are Gardnerian Wicca, adher strictly to principles laid down by Gardner and Alexandrian Wicca.

Christo-Paganism
Certain individuals and groups identify with both Christianity and Neopaganism, or in some cases with Christianity and some form of Historical Reconstructionism. They create their own syncretic spirituality from the aspects of both religions.

Unitarian Universalists
Unitarian Universalism is a non-dogmatic, non-creedal, individual search for truth. They seek to find individual truth, incorporating a variety of Pagan and non-Pagan beliefs; so most of them do not identify with any specific Pagan tradition. They can be considered Neopagans.

Related theological concepts

Animism
spirits inhabit every existing thing, including plants, minerals, animals and, including all the elements, air, water, earth, and fire. Since a spirit pervades every piece of living matter, an individual can absorb its essence by eating it. Ingesting the brains of a particularly clever creature will impart its intelligence to the ingester. Animism was probably the first form of religion/philosophy.

Panentheism
God is both immanent in creation and transcendent to it. God creates, contains and sustains the universe, but mysteriously exists outside of it as well. Subjectively, it can be explained as the feeling that nature, the universe, has a divine or awe-inspiring aspect. This is a form of monotheism.

Pantheism
god is the universe and the universe is god -- or, more generally, that the universe is literally Divine. Thus what happens in the universe is happening to god. If there is evil in the universe, then god is partly evil. Matter and spirit are two sides of the same coin. They come from the same source and share the same essential nature. Dualism is an illusion.

Dualism
There are only two fundamental things or substances or constituents of things in the world at large or in the human soul. Most commonly, this implies a God and a Devil-god, absolute good and absolute evil, or spirit and matter. Another example, from neopaganism, is the existence of a Goddess and God, neither of which is either good or evil, but each of which exists simultaneously and balances the other despite their mutual independence.
Polytheism is the belief in more than one god(dess). Polytheism often involves the worship of a heavenly pantheon of kindred gods, with one chief god who typically sits as lord. In addition, a polytheist may show respect to lesser spirits which are not part of the gods' pantheon, but which may be associated with specific localities, plants, elements, other-worldy realms, or mind-states. A polytheist may also believe in the existence of gods worshipped outside his own culture. In a form of polytheism more closely related to henotheism (such as Mormonism), one god is supreme and the others are ancillary and do not have the same level of godhead ("god-ness").
Henotheism is devotion to a single god while accepting the existence of many gods. Forms of late Greek and Roman classical religion were henotheistic. Some forms of modern Hinduism are also henotheistic.

Monism
Everything, possibly including multiple gods, is all part of a single god. Neoplatonism and most forms of modern Hinduism are also monistic.
Monolatrism is a type of polytheism. Its adherents believe that many gods do exist, but these gods can exert their power only on those who worship them. Thus, a monolatrist may believe in the reality of both the Egyptian gods and the god described in the Bible, but sees him or herself as a member of only one of these religions. The gods that he/she worships affect their life; the other gods do not. This reflects a form of solipsism and universalism.

Suitheism
The belief that deity is of one's own self without denying the existence of other god(desse)s. This is common in Thelema and among Left-Hand Path occultists.
Universalism is the belief that all religions are equal roads to heaven, although the adherent may chose only one or a few religions for his/her/its primary focus.

Criticism
The goddess worship is explicitly matriarchal, it thus marginalises men, just as Neopagans hold that women were marginalized in the past.

Neopagans cannot legitimately be considered practitioners of any "true" Pagan religion, as revivals are not identical to their models and can only be as true to the original as the reference material from which it draws
However, no accepted definition of the term "Pagan" requires unbroken continuity with earlier forms; the term is applied according to what the adherent believes, not according to the historical provenance of those beliefs. So while Neo-Egyptian spirituality may not be the same thing as its original, both are technically Pagan (albeit very different one)