Knowledge of war fighting in the digital battlefield is becoming more important due to the introduction of network centric warfare concepts. The key to success in cyberspace is to understand the prerequisites for conducting operations in the information arena and cognitive domain. Hence, for the Swedish Armed Forces (SAF), it is vital to develop useful theories, methods and strategies that give the ability to deal with new types of electronic and digital threats against information and information system as well vital infrastructure, networks, platforms and sensors. The purpose of this study is to develop theories and methods for modern warfare and its effects within the information arena and cognitive domain respectively, in line with the transformation to the network centric warfare concept. In the report different terms are discussed such as cyber warfare, hacking and cyber terrorism, electronic warfare and computer operations and the convergence between EW and CNO capabilities into a joint information operation tool. In order to describe effects from jamming, monitoring and deception methods built on effect matrix, actor-object-effect chains as well as combinatorics are used shown in five different case studies. The case studies discuss threats and vulnerabilities for both civilian and military systems.