This report sets out to identify key aspects related to the implementation of the Comprehensive Approach (CA) in Canada, the Netherlands and UK, based on previous case studies conducted by the Swedish Defence Research Agency (FOI). The cases studies provide no definitive blueprint for implementation of CA. Many differences exist between them; for instance regarding how CA is defined, how joint policies and documents are constructed (if any) and how CA is applied in the field. At the same time, many similarities exist, for instance, creation of interdepartmental structures, initiation of joint civil-military training and establishment of pooled funding. Canada, the Netherlands and UK also share some common difficulties when implementing CA; for example, reaching shared strategies and objectives across agencies and departments. The case studies show that some difficulties can be mitigated by creating permanent structures. Other instruments include exchange of staff members between departments, CAtraining and joint civil-military training in the pre-deployment phase. These instruments enable a mutual understanding among actors about each other's different assignments, cultures and working procedures. However, the most important experience, learned from the case studies, is that implementation of CA primarily is a 'learning by doing'-process. The development of tools is important, but it is when actors work with CA that they learn how to implement the approach. This demands a functional assessment process, which, unfortunately, is one of least developed parts of CA in all the three countries The success factors and pitfalls identified in this study do not constitute a panacea for implementing CA. They, rather, constitute key aspects that, if taken into account, increase the likelihood of a fruitful implementation of CA.