A nondisclosure agreement is part of a contract that can help to protect your trade secrets. When you hire a new employee, you may have to tell him or her some of these secrets in the course of production, research and development or some other part of the process. The agreement simply says that the employee legally agrees not to go elsewhere and use or sell that secret.
Patent law, like most other areas of law, has been shifting over the years. One of the more recent changes made the United States a "first to file" country. The grace period is nearly non-existent, and inventors and business owners need to file first to make sure their designs are secure.