I bought "Knife Fighting/Knife Throwing For Combat" recently, mainly because it is a "classic" and I collect books. Some act as if it is junk and others as if it is the best knife-fighting book ever written, and I've seen originals go for hundreds of dollars, so, to know the truth, spending $12.00 or so on Amazon wasn't a big deal. There is nothing special, it is mostly what I'd expect from a (non-FMA) martial arts book teaching knife use. IMO the movements are too big. I've seen worse in the MA magazines. SOme have said that rolling with a knife is too complex, but if you know how to roll then it is just rolling while holding a knife, though I'd agree that if someone is not trained to roll it would be difficult to learn to do so, especially with a knife, from a book.
In short, it isn't the worst book on knife fighting, but it certainly isn't the best. I don't get why it was "banned" by Ohara. It would have sold all these years like the other two in the series, and it isn't some super-secret or super-deadly manual or anything like that. Considering that it was out of print for many years, they couldn't have been using the marketing strategy to restrict a product for "police only" to create demand and then release it to the public.
I read an article by one John LaTourrette, one of Echanis' instructors, who said that Echanis wrote the books so he'd get publicity for his mercenary work, and that he hardly got any money from them. Before that I assumed that the concept of writing a book as marketing for your real business was a new one.