Rapid adaptation contributes to the capability of being able to quickly respond to unexpected threats or new military tasks. Short reaction time calls for other demands than what the ordinary defence acquisition process is designed to handle. This report has therefore studied the present situation concerning capability for rapid adaptation and suggests measures in order to realize an increased capability for rapid adaptation. The context is the Swedish national defence and the development in Swedens immediate surroundings. The report observes that there presently is a lack of an established capability to perform rapid adaptation. This concerns the entire sequence from identifying and assessing demand, taking decisions on and performing rapid adaptation. Five challenges are identified as especially important explanations for the shortcomings in the capability to perform rapid adaptation: 1) there is not an appointed function that collects and analyzes the need to perform rapid adaptation; 2) there is a lack of a methodology and responsibility for how an assessment shall be performed regarding the need for a rapid adaptation; 3) there is not an established decision making process for performing rapid adaptation; 4) it is unclear what competence is available for performing rapid adaptation; and 5) how the reintroduction, including the education need, of adapted systems shall be managed within a reasonable time frame. The report presents thirteen measures that individually and collectively contribute to an increased capability for rapid adaptation. These measures cover for example: identify defence systems that are especially likely to be subject to rapid adaptation; analyses should continuously be put together regarding technological and tactical changes that may lead to new demands for established defence systems in the Armed Forces; initiate demonstrator activities that will present insights on alternative options for adaptation of defence systems. The measures ultimately serve to strengthen the national defence capability by making the Armed Forces more flexible and prepared for dealing with unexpected paths of development. In conclusion, this reports assessment is that a capability for rapid adaptation contributes to increased freedom of action for the government in case of a worsened security situation and increased military preparedness. Our recommendation to the government is therefore to prioritize and strengthen the capability for rapid adaptation.