Bruce Tegner was an American who held multiple black belts. He had a special gift of being able to explain technique clearly using text and photographs. He was one of the most prolific martial-arts writers of all time, having published over 80 books on Judo, Jiu Jitsu, Karate, Savate, Yawara, Aikido, and various versions of self-defense.
Very early in my career (1970) I was fortunate to acquire a copy of Bruce Tegner's Complete Book of Self-Defense, originally published by Stein and Day in 1963. (Note that Tegner published more than one "complete book of self-defense," and publishers have reprinted the books over and over with different covers. They are not all the same book. Look for the Bantam Book version with the blue photo of Tegner demonstrating teisho uchi on somebody's chin. The cover mentions the "21-day Home-Study Course" with "Over 400 Photographs!")
Do you know how much effort it takes to produce 400 publishable photographs of martial techniques? Shotokan's Secret contains only 130, and it took months.
I thought the book was remarkable, and forty years later I still have a copy on my desk. It is the best-written self-defense book I have ever seen, assembled by a man with credentials in many arts. The teaching is clear, the techniques well-chosen, the advice sound. I particularly like the fact that he incorporated vital-point strikes from the very first day. The clarity of presentation was remarkable as was the message: You don't have to be black belt to use the martial arts. Anyone can learn these techniques.
He was an American who demystified the martial arts and made the techniques accessible to everyone. You would think his name would be a household word in our circles. Most of my friends have never heard of him.
Some people take years to climb the mountain. A few like Tegner just step over the mountain as if it were not there.