One of the essential elements of a patentable invention is novelty. Consequently, disclosure of your invention to others may severely restrict, and can completely eliminate, your ability to claim patent protection in the United States and elsewhere^[note]. There are many factors that must be considered in determining whether a disclosure is of a type that will affect your claim of patent protection, especially where patent protection in more that one country is sought. In the matter of disclosure of your invention you are best advised to consult and work with an attorney.

In general there are two types of disclosure, public disclosure and confidential disclosure. Public disclosure abolishes novelty and limits or destroys your ability to obtain patent protection; restricted confidential disclosure maintains novelty and preserves the opportunity to claim patent protection. Set out in the table below, in general terms that apply more or less universally, are the broad definitions of disclosure and its effects:

Public Disclosure		Confidential Disclosure
Any publication[note] or public utterance anywhere in the world describing the invention, or any public display of the invention. Any public use of the invention or distribution of articles produced by, resulting from, or derived from the invention, or any offer for sale of the invention.	General Definition	Any disclosure made for the purpose of testing, research, and development of the invention under an understanding or expectation of confidentiality. Most disclosures made under a written or express agreement of confidentiality and non-disclosure.
The inventor must file an application for patent protection within 12 months after the date of publication anywhere, or of public use or offer to sell in this country.[note]	Effect in the United States	Provided that the inventor applies for patent protection within a "reasonable" period from the time that the invention has been reduced to practice[note], the ability to claim patent protection endures.
The opportunity to claim patent protection is lost.	Effect in Most Other Countries	Provided that an inventor files a patent application before anyone else does, the ability to claim patent protection endures.

While the above rules apply generally, there are important differences among countries in the way particular instances of disclosure may be treated as public or confidential. For example:

In the United States (regarding applying for patent protection in the U.S.),

• a disclosure for the purpose of selling the invention, especially for the purpose of gaining a marketing advantage, is considered a public disclosure, even when made under an agreement of confidentiality;
• a confidential oral disclosure is generally not considered a public disclosure, nor is a public oral disclosure, use, or sale that is made outside of the United States; but
• any written or otherwise-recorded report of an oral disclosure, or any documentation of any kind that reveals the invention, to which the public has access (whether or not anyone actually looks at it), is a public disclosure.

[The U.S. law on disclosure and loss of patent rights.]

In most other countries (regarding applying for patent protection in those countries),

• a private offer to sell the invention is usually not taken to be a public disclosure; but
• an oral disclosure or display of an invention anywhere in the world may be a public disclosure.

Note that Canada, like the United States and unlike other countries, affords a 12-month grace period in which to file a patent application after public disclosure has been made.

In addition, note that patent applications in most countries are "laid open" (i.e., made public) 18 months after they are filed. Publication of a patent application in this way will affect your claim of patent protection, elsewhere, in the same way that any other public disclosure would.

It is possible to apply for patent protection in more than one country concurrently. Generally an application is filed first in the country in which the inventor resides or has citizenship. There are rules governing which country must be the country of origin. In the United States, for instance, application for patent protection of an invention that was "made" in the U.S. must be first filed in the U.S.

Once an application has been filed in one country, applications may then be filed within 12 months of the first application's filing, in other countries that, by treaty or legislation, have reciprocal priority agreements with the country of first filing. In those cases covered by treaty or bi-lateral law, disclosure of the invention after filing the first application and before subsequent applications are filed will not destroy novelty with respect to those other countries.

Under the Patent Cooperation Treaty (PCT) in particular, it is possible to file a single application by which your opportunity to apply for patent protection in any of the 100 PCT countries may be maintained, regardless of subsequent disclosure, for at least 20 months, and for as long as 31 months under certain conditions.