Between mid-2015 and 2020, as research for a doctoral thesis, I interviewed over 50 military personnel who were directly involved in a role advising a partner security force. This included Australian Defence Force (ADF) personnel who participated in mentoring task forces, train-advise-assist (TAA) roles, Defence Cooperation Program (DCP) initiatives and several other one-on-one or team advisory duties. The research also included interviews with allied personnel from the United States Army, particularly where they had been involved in joint initiatives with the ADF. Interviews also included host-nation personnel from the Afghan National Security Forces and Papua New Guinea Defence Force (PNGDF), to provide the views of personnel being advised or mentored, to determine what mattered to them and to obtain an alternative perspective. Interview subjects ranged in rank from sergeant to four-star US general, to garner both tactical and command perspectives.