This book traces the roots of the Oneness Pentecostal movement to Pentecost and then highlights personages in the early centuries who were Oneness in theology and baptized in Jesus' name. The book also gives a brief overview of the secular of El Salvador. The main thesis of the book is the Oneness Pentecostal movement traced from Frederick Mebius and the Apostolic Church of the Faith in Christ Jesus and The United Pentecostal Church International of El Salvador.