Book excerpt: This book discusses a broad range of cyber security issues, addressing global concerns regarding cyber security in the modern era. The growth of Information and Communication Technology (ICT) and the prevalence of mobile devices make cyber security a highly topical and relevant issue. The transition from 4G to 5G mobile communication, while bringing convenience, also means cyber threats are growing exponentially. This book discusses a variety of problems and solutions including: • Internet of things and Machine to Machine Communication; • Infected networks such as Botnets; • Social media and networking; • Cyber Security for Smart Devices and Smart Grid • Blockchain Technology and • Artificial Intelligence for Cyber Security Given its scope, the book offers a valuable asset for cyber security researchers, as well as industry professionals, academics, and students.