Linda Hall Library is one of over 85 libraries in the United States that participate in the Patent and Trademark Depository Library (PTDL) Program. The PTDL Program is administered by the U.S. Patent and Trademark Office.

Through the PTDL Program, the U.S. Patent and Trademark Office (PTO) provides participating libraries with a variety of patent and trademark information and resources, including tools for patent and trademark searching. The PTDL Program webpage lists basic materials/services available at PTDLs.

As a PTDL, the Library also receives all U.S. patents. The collection covers 1790 to present. Most are on optical disc. Some are available on microfilm or paper.

PTDLs are provided with tools that can be used by the general public to conduct patent searching. Conducting a patent search is a complicated and time-consuming process. Reference librarians can explain the steps involved in a patent search using the U.S. Patent Classification System. See the PTDL Program's webpage for a description of the steps involved in conducting a patent search at a PTDL.

The completeness or accuracy of a search rests entirely on the individual doing the search. Reference librarians cannot conduct searches for patrons, nor provide legal advice or opinions. Users are urged to consult a patent attorney for legal advice. Appointments are encouraged for individuals new to the process of doing a patent or trademark search.

All PTDLs receive the CassisTM series of files on DVD-ROM. These searchable files contain patent and trademark information and are produced by the U.S. Patent and Trademark Office. Detailed information on the contents of each of the Cassis files is listed on the PTO's website.

For more information concerning the PTDL Program, contact the Library's Reference Department.

Following are some other useful pages from the United States Patent and Trademark Office's website.

• General Information Concerning Patents patent brochure available on PTO's website.
• PTO's searchable patents database on their website.
• Basic Facts About Trademarks trademark booklet available on PTO's website.
• Trademark Information on PTO's website - includes link to TESS, the PTO's searchable trademark database.

Following are some other patent and trademark related websites:

• U.S.Code, Title 35 Patents
• U.S.Code, Title 15, Chapter 22, Trademarks.
• World Intellectual Property Organization website.
• European Patent Office website. Includes link to "esp@cenet" worldwide patent database.
• International Trademark Association website.