Manual of Patent Examining Procedure
The Manual of Patent Examining Procedure (MPEP) is published by the United States Patent and Trademark Office (USPTO) for use by patent attorneys and agents and patent examiners. It describes all of the laws and regulations that must be followed in the examination of U.S. patent applications, and articulates their application to an enormous variety of different situations.
Source: Wikipedia — Manual of Patent Examining Procedure (CC BY-SA 4.0)