Explain the basic principles of the law of evidence.

The relevance's discipline: the proof confined to the facts in issue-and-the relevant facts (U3's definitions) — the court's time-and-attention protected from the irrelevant. The operations: the pleadings' definition of the issues (the civil case's scope); the charge's frame (the criminal case's scope); the court's exclusion of the collateral matters (the wandering testimony's control); the discretionary exceptions (the background-and-context evidence — the story's necessary scene).