RCIA -- Rite of Christian Initiation of Adults -- is the process through which the Church welcomes new adult members.  It is a journey that involves conversion of the heart and formation into discipleship.  These newcomers may be unbaptized persons, persons who have been baptized in another Christian tradition, or baptized Catholics who have had little or no religious training.  Ideally, this process of formation spans a complete liturgical cycle (one year) beginning with the precatechumenate or inquiry period in the late spring or early summer, reaching a high point with the reception of the initiation sacraments (Baptism, Confirmation, and Holy Eucharist) at the Easter Vigil, and concluding with a period of reflection and continuing formation after Easter.  Of course, the working of the Holy Spirit in people's lives does not always conform to human schedules.  So, the process sometimes takes a shorter or longer time.