Absolutely Free, by Zane Hodges and Sin, the Savior and Salvation, by Robert P. Lightner. Lightner's book is by far the best of the four. It is the most scholarly of the four. It refers to a new generating, a new genesis, a new beginning. The Spirit recreates the human heart, quickening it from spiritual death to spiritual life.
Regenerate people are new creations.
Regeneration is not to be confused with the full experience of conversion. Just as birth is our initiation, our first entrance into life outside the womb, so our spiritual rebirth is the starting point of our spiritual life. It occurs by God's divine initiative and is an act that is sovereign, immediate, and instantaneous. An awareness of our conversion may be gradual. Yet rebirth itself is instantaneous.