Recently I read a book by a well-established and reputable self-help organization. It taught that self-confidence is an external manifestation of one's self-esteem.

I don't agree.

Or, more accurately, I don't find that sort of education helpful.

Self-confidence is a state of mind that defines how a person thinks and feels about his or her ability to successfully handle a given situation¹ [or, at least, survive it]. Presence of self-confidence is a Good Habit². Lack of it is a Bad Habit³.

Self-esteem is a state of mind that defines a person's regard for self.  It too can be composed of Good Habits or Bad Habits.

Self-esteem doesn't generate self-confidence. If anything, the opposite is more likely to be true. Regardless, it seems to me the important thing to do is concentrate on building self-confidence. To the extent a person succeeds at building self-confidence, that person's self-esteem will increase. The path to building self-confidence is paved with Courage.

Footnotes:

1. A situation is a snapshot of an instant in business life…the people, the ‘props’, and the immediate environment.
2. A Good Habit is a thing we think or do that takes us towards our goals.
3. A Bad Habit is a thing we think or do that takes us away from our goals.