Leadership is written for the individual who is the leader, and for the challenges that come only with that role.
It is about how to be a leader, and how to inspire confidence in the people who follow you. The leader shoulders the burden. They motivate the team and shield it from what would distract or discourage it. They act as the diplomat, holding several truths at once and speaking to each person in terms they can accept. And they do the worrying on behalf of everyone else, so the team can get on with the work.
It is also about what happens inside your head when you are alone with a decision, and nobody else can share it.
And it is honest about the uncomfortable part. Sometimes the leader has to be vague. Sometimes they have to hand out certainty when they know the odds could go either way, because a team that sees its leader doubt stops moving. Knowing when to do that, and how to live with it, is part of the job.
None of this appears in a job description, and none of it shows in the accounts. It is learned the hard way, usually alone.