A document disclosing an invention, and signed by the inventor or inventors, that is forwarded to the USPTO only as evidence of the date of conception of the invention. The disclosure document may be forwarded to the USPTO by the inventor (or by any one of the inventors when there are joint inventors), by the owner of the invention, or by the attorney or agent of the inventor(s) or owner. A disclosure document is not the only type (and not necessarily the best type) of evidence of the date of conception of an invention. Notarized records or a conventional, witnessed, permanently bound, and page-numbered laboratory notebook may also serve as evidence of the date of conception of an invention.