An invention is to be "considered novel if it is not anticipated by the prior art". The "prior art shall consist of everything which has been made available to the public anywhere in the world by means of written disclosure (including drawings and other illustrations) and which is capable of being of assistance in determining that the claimed invention is or is not new and that it does or does not involve an inventive step (i.e., that it is or is not obvious), provided that the making available to the public occurred prior to the international filing date". The scope of this definition should be noted. There are no restrictions whatsoever as to the geographical location where or the language in which the relevant information was made available to the public; also no age limit is stipulated for the documents or other sources of the information.
The principles to be applied in determining whether other kinds of prior art, e.g. relating to use (which could be introduced e.g. by a third party, see GL/PCT‑EPO E-II, ISPE Guidelines 16.57 and PCT/AI section 801), have been made available to the public are governed by Rules 33.1(b) and Rules 64.2.
A written description, i.e. a document, should be regarded as made available to the public if, at the relevant date, it was possible for members of the public to gain knowledge of the content of the document and there was no bar of confidentiality restricting the use or dissemination of such knowledge. For instance, German utility models ("Gebrauchsmuster") are already publicly available as of their date of entry in the Register of utility models ("Eintragungstag"), which precedes the date of announcement in the Patent Bulletin ("Bekanntmachung im Patentblatt").