Cyber war and cyber-attack is an engaging review of the basic knowledge all up to date readers should have about cyber war and cyber-attacks before diving into more complex texts, as well as extra information for those already familiar with the topic. This work takes a look at general issues involving cyber vulnerability and our growing dependency on computers systems and networks. It goes beyond simple concepts such as hackers, hacktivism and espionage without neglecting them. It exposes the relevance of cyberdefence to both companies and ordinary users, giving especial attention to e-commerce platforms. At a time that many countries are employing strategies and money to prevent or minimize attacks as well as defend themselves against cyber threats this work pinpoints the key factors around the intentions behind attacks without minimizing their scale and variety. The jargon-free language and the current examples included help to set the discussion in the present day, while stressing important historical connections and pointing to how our strong network is at risk of becoming our weakest link.