Born again is a common term in contemporary religious dialogue, referring to a transcending personal experience—or the experience of being spiritually reborn as a "new" human being. In psychological terms, being "born-again" is perhaps analogous to a perceptual state of hyper-salience; where one experiences an extreme and jarring change of perceptions, causing a re-awakened and renewed sense and understanding of oneself and ones relationship to the world/universe.
The Christian use of the term is derived from the third chapter of the Gospel of John, where Nicodemus asks Jesus what he must do to be saved:
Now there was a Pharisee named Nicodemus, a leader of the Jews. He came to Jesus by night and said to him, "Rabbi, we know that you are a teacher who has come from God; for no one can do these signs that you do apart from the presence of God."
Jesus answered him, "Very truly, I tell you, no one can see the kingdom of God without being born again."
Nicodemus said to him, "How can anyone be born after having grown old? Can one enter a second time into the mother's womb and be born?" Jesus answered, "Very truly, I tell you, no one can enter the kingdom of God without being born of water and Spirit."
-John 3:1-5 (New Revised Standard Version)
Note that some translators consider "born from above" to be a better translation than "born again"
Most Christian denominations would agree that a true Christian must be born again, based on the above passage, and thus that those who are true Christians are in fact born again, whether they describe themselves as such or not. The Roman Catholic church, for example, considers that "Baptism is ... the sacrament by which we are born again of water and the Holy Ghost" . However the term is most frequently used by EvangelicalProtestants, where it is often associated with an intense conversion experience and an encounter of the individual with the power of God. Some would deny that those without such an experience are true Christians, based again on the above passage. It is common to find that Christians who describe themselves as born again consider those who do not to be counterfeit.
The idea of born again carries with it the theological idea that a Christian is a new creation, given a fresh start by the action of God, freed from a sinful past life and able to begin a new life in relationship with the Holy Spirit.
Born Again is also the title of a book by Charles W. Colson, which describes his experience of becoming a born again Christian.
Almost all Christians associate the Kingdom of God with acceptance by God, and by implication with the removal and forgiveness of sins, which are seen as separating one from God. A minority might disagree with this.
In research into near death experiences, some people recall a passage along a tunnel towards a light. The apparent relation of this to the birth experience leads some researchers to consider that death is a kind of 'second birth', and therefore that we can be 'born again' at death.
Some propose a resonance between aspects of Christian "Born again" doctrine and some aspects of reincarnation theories known from Hinduism and Buddhism. There are probably at least as many who don't see any relation, however.