Books can be attributed to "Anonymous" for several reasons:
* They are officially published under that name * They are traditional stories not attributed to a specific author * They are religious texts not generally attributed to a specific author
Books whose authorship is merely uncertain should be attributed to Unknown.
This was actually a very well done book, given the era it was published in. Some of the methods seem fairly sound.
The Shanghai Municipal Police were noted for their ability to fight, and they synthesized various systems together to come up with a rough and tumble method that was reputed to work. Two of the most famous veterans of this force were William Ewart Fairbairn and Eric Anthony Sykes. This particular text doesn't credit either of these gentlemen as having contributed to the work.