Charles David Henderson
I always took pains to write, through the years, only what I knew was demonstrably true because I was well aware that things come back to haunt. However, as in any other skill, what I know now far exceeds what I knew then and I think that there are more concise, broader views of these skills than what I wrote back then. In other words, I don't recommend those old writings because while they're roughly true, they don't present the information that you need, very well. I toss out that caveat in the interests of trying to save people time.
In terms of "aiki" (various jin/kokyu skills and their use), there are various levels and my main suggestion is for people to first get their feet wet and experience what the skills look like. My second suggestion is that no one assume that what they now know is a final or polished view. I've seen a lot of people make the horrible mistake of thinking they already have it and it dooms not only them but the people they teach. This is why arts lose these skills.