St. Augustine famously referred to the Easter Vigil as the mother of all holy vigils. It was the night he was baptized, as a previously reluctant adult, by Bishop Ambrose in 387 C.E.
The vigil is composed of four key elements: 1) the service of Light as a fire outside lights the paschal candle, which is then brought into the dark sanctuary. 2) The Liturgy of the Word: five great Old Testament stories are told in creative fashion, and two New Testament readings declare the history of salvation. 3) Baptismal Liturgy: we remember our baptismal promises and Gods grace outpoured. 4) The first Eucharist of the Resurrection.