Introduction In order to reach their operational goals@ NATO/Nations/Agencies develop strategic objectives that are realized by single or multiple capabilities. Capabilities are realized by single or multiple programmes@ and programmes are realized by single or multiple projects. A programme is undertaken to develop a system@ product@ or a service that feeds into this framework. Ongoing organisational activities/processes are aligned to support the needs of the programme. As described in the NATO Policy for Systems Life Cycle Management (SLCM)@ the aim of SLCM is to optimise defence capabilities over the life cycle of the system by taking into account performance@ cost@ schedule@ quality@ operational environments@ integrated logistic support@ and obsolescence. It facilitates interoperability@ communication@ collaboration@ and cooperation@ while minimising total life cycle cost. Annex 1 shows the big picture of the Life Cycle Framework. AAP-20 is a generic guidance document which provides the standardized and tailorable approach for managing programmes that includes materiel solutions and should be used in conjunction with AAP-48 and the SLCM document Library. AAP-48 defines the NATO System Life Cycle Management processes. The SLCM document library contains procedures@ templates@ handbooks@ and other documents. Purpose AAP-20 is a generic guidance document that provides the standardized and tailorable approach for managing programmes by NATO@ Agencies@ Groups of Nations and Nation(s). It delivers a structured approach to describe the stages and to aid decision-making at these decision points for all management levels involved in cooperative programmes. This document focuses on the formulation of requirements based on a capability gap and the management of a programme throughout the life cycle@ including accelerated fielding (rapid acquisition) and technology insertion. It provides potential pitfalls@ risks@ and opportunities for managing a programme based on the best practices of NATO Nations and helps clarify the roles of the National and NATO Authorities and the International Staff in the decision process. AAP-20 expects close cooperation between operational commands@ military planners@ and programme managers. Stakeholder requirements will be provided by military planners to programme managers based on capability gaps and strategic objectives. Applicability Nations are encouraged to use this publication as a guide and therefore@ AAP-20 intends to support and complement national acquisition policies@ not replace them. The use of AAP- 20 in NATO@ Multinational and National Programmes as an enabling framework will lead to a more effective and efficient provision of capabilities. With the necessity to describe interfaces and relationships to other processes and domains@ it was necessary to use the NATO processes and domains to show the dependencies. Nations@ Agencies@ and other Users of this guideline should adjust these interfaces to their appropriate processes and domains.