Cyber Security has become an absolute necessity. Today no device can be connected to the Internet without proper security in place. Every year millions of users fall victim of malware and cyber attacks. How should we ensure our cyber security then? The best way to prevent an attack is to understand how the attack works, what are the main motivation of the attackers behind the attacks, what all preventive measures we can take and how those preventive measures actually help. A Guide To Cyber Security is a book which explains how various malware and cyber attacks work, why attackers make such attacks and how we can effectively prevent them. The book covers topics like Encryption, Security of Online Accounts, Email Security, Phishing, Malware, Ransomware, Security of Mobile Phones, Privacy and Security while browsing the Internet, Security of IoT, Blockchain etc. Also, the book is written keeping all internet users in mind, so that all the readers can benefit from the book.