How Secret is Freemasonry?
Answer: Not very if at all.
It is rather hard to be secret with probably billions of words having been printed about the Fraternity.
If Freemasonry is attempting to be a Secret Society, it has failed. It has probably attempted to be a Secret Society in countries where it was outlawed. In most countries worth living in the Freemasons do not attempt to hide their existence and most Masons are proud of their membership.
As far as I can tell absolutely everything about Freemasonry has been published in various books and on the Internet, however a lot of what has been published is simply not true.