How do I find a patent?

• Patent searching is the process of researching previous patents relevant to a specific invention or idea.
• Before beginning to build a prototype of your invention, you should do a patent search to ensure that your idea has not already been patented.
• Searching for prior patents relevant to your own invention helps you demonstrate how you have distinguished your invention from previous inventions.
• Patent searches are essential because during the patent application process, you must submit the findings of your patent search with your patent application.
• Failing to conduct a comprehensive patent search could result in the validity of your patent being challenged in the future.

The MIT Inventor's Handbook offers a great introduction to patent searching. 

•  Google Patents provides an extensive collection of searchable patents.
• Try Google's Advanced Patent Search for more search options and fields.