I'm going to go against the grain on this one. Some topics are just really really difficult. Even if you have a few examples of a principal, it can be very hard to figure out a general rule. And even if a person comes up with abstract rules for how to accomplish a goal, it can often be difficult to realize all of the most important ways that that rule should be applied. And that's not to mention, even if a person is great at a task, that doesn't mean that they will be able to articulate why, or teach others how to be good at the task as well. Personally I think there are some topics that nobody on Earth is qualified to write a book on.

If you aren't confident, then there's no need to share your thoughts with others, no matter how important the topic. But then again, if you ARE confident in your beliefs, or your actions depend on others, then I don't even care if you are wrong; I want to hear what you have to say.