A translation of an extremely rare book on the link between Ninjutsu and Senjutsu, the arts of the mountain ascetics. This is a bilingual edition with both English and Japanese. Originally published in 1901, this book marks the beginning of the Ninja boom, that happened in early 20th century Japan. By 1920 there were dozens of books about Ninja and Ninjutsu as overall interest in the supernatural increased.
As usual, Shahan's translation is pleasantly straight-forward and I appreciate his bilingual presentation. I think the text overall is more of a historical curiosity than anything, but I read a lot of historical curiosities, so I'm not going to complain.