Once an innovator has conceived of a new invention and is seeking to make it real by “reducing the invention to practice,” it is important both to describe the invention as thoroughly and clearly as possible and also to identify the closest substitutes for the invention both in the patent literature and in the public domain. This identification process can involve searching public databases of patents and patent applications from around the world. It is critically important for the invention to be described so as to occupy as much conceptual territory as is practical and to be claimed so as to be clearly distinct from any previous inventions. To do so requires close cooperation between innovators and patent counsel.
The resources below provide additional information about patent law. They cover a range of subjects, from what the requirements of patentabilty are, how you get a patent, and information about patent infringement and enforcement. If you dig around these sites and keep exploring, you’ll gain all kinds of very useful information, regardless of whether you ultimately need to hire a patent lawyer or not.