Im not sure on any book titles, but there are definately a huge collection out there, but try finding something on Oak Island. It is something that hugely interests me and I love reading about, although I do mine mainly online to avoid the bia opinion of a book....Basically, Island in Canada...Two kids found a slight hole like feature in the ground one day, below a tree that looked like it had been adapted as a pulley. They started digging...From then on, no one has been able to dig to the bottom...as every 10 or so feet, there are log, chests and other such things blocking the way....there are also tunnels coming into the main ditch that flood the entire thing if any one digs that far...Its like a giant puzzle that even in todays modern age no one can solve...So still no one knows what is at the bottom (if anything). There are a wealth of theories as to what lies at the bottom though, and as the search still goes on, tis something you can keep upto date with.