Mandaeanism is a pre-Christian religion which has been classified by scholars as Gnostic.
Since the 1st century AD the Mandaeans have mainly lived in the borderland areas of Iraq and Iran. Many have fled the region since the 1990s due to the unstable political climate and have immigrated worldwide. There is no official census of the Mandaeans; conservative guesses at current population size have been made in the range of 50,000 to 70,000.
In reference to their connection to the Qur'an as the Sabians, Mandaeans are called Subi by their Muslim neighbors. The Mandaeans have also been called the "Christians of St. John" (a misnomer, since they are not Christians) based on a comment made by Portuguese monks in the 16th century. The Mandaeans may also be the same "Nasoraeans" indicated in the works of Epiphanius. The Mandaeans have remained separate and intensely private- what has been reported of them has come from outsiders.
The Mandaeans are labeled as gnostics due to the Mandaic word manda, which can be translated into knowledge, the same word as "gnosis" in Greek. Thus Mandaeanism can be seen as a "Gnostic" religion. It is the only remaining Gnostic religion excluding revivals like the Manichaean Orthodox Church  still in practice.
Part of the Mandaean ritual dress, called a rasta , includes a white turban symbolizing the great mystery of radiance, light and glory.
The Mandaean religion has a more strict dualistic nature than most Gnosticism. Instead of a large pleroma, for the Mandaeans there exists a clearer division between light and darkness. The ruler of darkness is called Ptahil (similar to the Gnostic Demiurge), and the originator of the light (i.e. God) is only known as "the great first Life from the worlds of light, the sublime one that stands above all works". When this being emanated, other spiritual beings became increasingly corrupted, and they and their ruler Ptahil created our world.
Mandaeans believe that Abraham, Moses, Jesus, and Muhammad were false prophets; instead they acknowledge John the Baptist, whom they see as one of their greatest teachers. There is some confusion that the Mandaeans came after John the Baptist, while in fact they existed before him; according to Mandaean dogma, Mandaeanism was the original religion of Adam. In the Mandaean library of scriptures there is a book of John called Sidra d Yahia, which includes a dialogue between John and Jesus. They also have a hierarchical clergy, practice frequent baptism, and hold public worship on Sundays. They deplore fasting and monasticism, and believe in peace above all.
There are many Mandaean scriptures, the most important being the Ginza Rba, a collection of history, theology, and prayers. On the Internet, the Ginza Rba is often confused with the Qolusta , which was translated by E.S. Drower in her book titled "The Canonical Prayerbook of the Mandaeans". The language used is called Mandaic, a language closely related to Aramaic.
According to the Fihrist of ibn al-Nadim, Mani, the founder of Manichaeism, was brought up within the Elkasite (Elchasaite) sect. The Elchasaites were a Christian baptismal sect which were likely related to the Mandaeans. The members of this sect, like the Mandaeans, wore white and performed baptisms. They dwelled in East Palestine and Northern Mesopotamia, from where the Mandaeans came to Southern Mesopotamia according the Harran Gawaitha legend. Mani later left the Elkasaites to found his own religion. In a remarkable comparative analysis, Mandaean scholar Säve-Söderberg demonstrated that the Mani's Psalms of Thomas were closely related to Mandaean texts. Mani must have had access to Mandaean religious literature. This leads to the question of just how close the origins of the Elchasaites, Mani, and the Mandaeans are to one other.
- Mandaeans.org - Majority of the information is in Arabic. Nice site from the United Kingdom.
- Mandaean World- Information on the Mandaeans including history, the Mandaic language and Literature
- Mandaean scriptures: Ginza Rba and Haran Gawaitha texts and fragments -- Take note the book titled Ginza Rba is not the Ginza Rba but is instead "The Canonical Prayerbook of the Mandaeans" as translated by E.S Drower.