The Tallinn Manual (originally entitled, Tallinn Manual on the International Law Applicable to Cyber Warfare) is an academic, non-binding study on how international law (in particular the jus ad bellum and international humanitarian law) applies to cyber conflicts and cyber warfare. Between 2009 and 2012, the Tallinn Manual was written at the invitation of the Tallinn-based NATO Cooperative Cyber Defence Centre of Excellence by an international group of approximately twenty experts. In April 2013, the manual was published by Cambridge University Press.