The non-disclosure agreement is the most-signed and least-read contract in commercial technology practice, and a startling share of them protect far less than the parties assume. This UpLaw guide dissects the NDA provision by provision—the definition of confidential information, the split between non-disclosure and non-use, the standard exclusions, marking discipline, term and survival with perpetual trade-secret protection, compelled-disclosure and return-of-materials mechanics, and the remedies architecture that makes an injunction reachable. It gives sustained attention to the problems technology deals create and boilerplate handles badly: protecting source code and model weights, the residual-knowledge fight, contractual reverse-engineering bans and their statutory limits, and the DTSA Section 1833(b) whistleblower-immunity notice whose omission quietly forfeits double damages and attorney's fees. A running hypothetical—an agricultural-AI startup opening its models to a large equipment maker—keeps the doctrine concrete. The aim is a working framework for building agreements that protect what matters, not documents that merely look protective until a court reads them.