Today, the term 'secret society' seems somewhat ironic. Arguably the most famous one - the Freemasons - really isn't all that secret. The group's rites and rituals might be steeped in mysticism and symbolism, but much has been written about the group that appears in the public domain.
Many people have heard of the Illuminati, of Skull and Bones and of the Rosicrucians. But what about the clandestine groups that were, in fact, more secret? The ones that nobody remembers any more; the ones that thrived - and died - in the shadows?