This volume is an historical survey of advisory and mentoring missions from the 1920s onwards, starting from the Soviet missions to the Kuomintang and ending with the mission to Iraq. It focuses on Afghanistan during the Soviet occupation and after 2001, but also deals with virtually every single advisory mission from the 1920s on-wards, whether involving 'Eastern Bloc' countries or Western ones. The sections on Afghanistan are based on new research, while the sections covering other cases of advisory/mentoring missions are based on the existing literature. The authors highlight how large scale missions have been particularly problematic, causing friction with the hosts and sometimes even undermining their legitimacy. Small missions staffed by more carefully selected cadres appear instead to have produced better results. Overall, the political context may well have been a more important factor in determining success or failure rather than aspects such as cultural misunderstandings.