First off, that's not a ninja. That's what happens when a kid is so irretrievably fucked they don't even bother the Make-a-Wish people, they just change his pajamas and tell him he's a silent assassin and should practice being ignored. In the book it appears exactly like that - no caption, no figure, no reference in the text, just some guy in black cloth with more tassles than a stripper and a target market which honestly that kicked ass. That couldn't kick a kitten in a boot-testing factory. Because this was in 1986, just after Karate Kid and American Ninja, when the common sense part of every brain under fifteen was destroyed by shurikens.
Now it's been brought forward in time by the eternal-mistake-preserving technology of the internet. So if Facebook got your ass fired for flashing at a frat party, don't worry: it's making up for it by mutilating Naruto fans. This book is extremely popular again on torrents, and a decades-old resurrectee hasn't maimed this many people since the Halloween movies.
If you've spotted that knife-throwing is the worst self-defense mechanism possible, felonious enough to get your ass arrested while ineffective enough to ensure the police have to scrape you into the cell, this author agrees with you - if only subconsciously. Even in his own book dedicated to blade-hurling he starts off with a fan-fiction, set in the days before guns, and still need six pages to invent a situation where throwing knives comes in handy. If you're a fan of "reading" you'll want to skip this part: It makes the average Harry Potter/X-Men crossover seem well-written, and is probably most brain-damagingly bad piece of literature short of being hit in the head with a hardback DaVinci Code.
After showing his homeroom English teacher that he can-so-too get published Mr Peters gets on to the real meat of the book: advising psychotic shut-ins to start carrying knives. This is it starts moving from "crappy cash-in" to "check you don't live near the author." He advises all readers to throw their knives six hundred times a week, which sounds like a great way to turn Obsessive-Compulsive Disorder into a horror movie script, and then carefully explains how knife-throwing is obviously useless unless you carry knives with you every waking moment.
The book also handily removes the readers from the gene pool, because any "date" who hangs around after seeing this picture in your flat is an undercover police officer.
The advice ends up exactly neutral for the non-stab-fan: there's the scary way he tells amateur knifologists to make sure they're always armed, but it's perfectly cancelled by the insane hiding places he comes up with: in your armbands, within your sash, or tucked into your headband or mask wrappings. So any newly-bladed practicioners are already avoided in the street by anyone not currently studying for a Doctorate in Crazy. Besides, anyone walking down the street in a full blade-stuffed sash and Naruto headband had better hope the police find them before anyone else.
Unless, of course, they meet another ninja!
Of course you have to train for various situations where you might meet another ninja - though if you're both really ninja, the chances of seeing each other are on par with two Kate Mosses being in the same Dunkin Donuts. This guy is really preparing for a life of ninja combat - it seems a shame to be so far into a world of delusion without getting a jetpack or a cheerleader. But at least it's encouraging the audience to meet each other, practice knife combat, and help evolution on a little.
This is where I realised the publishers behind this book are geniuses. The author might need to be restricted to sporks, but they're selling this insane crap to people who will never be able to complain. Because you need fingers to work phones, or type, and the sort of person who learns knife throwing out of an online book is about twenty self-assertiveness lessons from the confidence to order at a drive-through. Never mind complaining about someone who owns knives.
It's still the most irresponsible printing since "My First ABC of Cleaning Products That Look Like Fruit Juice," but they've made sure that there are hundreds of miles between them and the involuntary injury machine they've unleashed. In fact, it may be the reincarnated spirit of Charles Darwin working to assist natural selection after deciding - as any intelligent person must - that the first to be purged from the modern world must be white people who say "Bakka".
I have to believe that this secret eBook cabal is working to improve humanity. The only alternative is that author "Michael E. Peters" is a real person walking around loose.