Some background information

The conception of Neon Genesis Evangelion relies heavily on old Jewish mysticism like the Qaballah, apocryphic books and Christian belief in general, though I don't think that a religious message was intended in doing so.
Nonetheless, it it useful to have at least a basic knowledge of what this is about to understand the background of Neon genesis Evangelion.
As I don't claim to be an expert on that field, my explanations will be too short, too inaccurate and sometimes false as well, but the interested reader will be presented some linke to start his/her own studies.