The written record about these religions was for a long time a record of policing. Brazilian law criminalised practices associated with the terreiros well into the twentieth century, and much of the early documentation is court, press and medical material produced by people arguing that the religion was a public danger or a pathology.
Early Brazilian scholarship was entangled with that argument, and some of it applied racial theory directly to the question of what the religion was. Later ethnography, from the mid twentieth century, is far better and carries its own bias: researchers worked with a small number of prestigious Bahian houses, and the picture of Candomble that entered the literature is disproportionately the picture those houses presented.
The tradition's own transmission is oral, musical and embodied, held in the songs and drum rhythms that call particular orixas, in the obligations of the house, and in what is taught to initiates in stages over years. It was not designed to be legible from outside and is not fully legible now.
Since the late twentieth century, practitioners have themselves become authors and scholars, and terreiros have pursued heritage recognition and legal protection, which has changed both the record and who controls it.
The atlas describes the structure of the pantheon and the character of the institutions. It does not reproduce liturgy, and it does not describe an initiation that the traditions hold closed.