In today’s digitally interconnected world, the threat landscape has evolved to include not just sophisticated technical exploits but also the art of human manipulation. Social engineering attacks have emerged as a formidable and often underestimated threat to information security. The primary aim of this textbook is to provide a comprehensive and in-depth exploration of social engineering attacks. The book seeks to equip cybersecurity professionals, IT practitioners, students, and anyone concerned with information security with the knowledge and tools needed to recognize, prevent, and mitigate the risks posed by social engineering. The scope of this textbook is broad and multifaceted. It covers a wide range of social engineering attack vectors, including phishing, vishing, pretexting, baiting, tailgating, impersonation, and more. Each attack vector is dissected, with detailed explanations of how they work, real-world examples, and countermeasures. A packet sniffer is a technique for intercepting network packets or a type of spyware that hackers use to track individuals connected to a network. Although packet sniffing technologies are used by network administrators to monitor and verify network traffic, hackers may employ similar tools for unethical objectives. A WIFI adapter with monitor mode and packet sniffing capability is the most crucial item for packet sniffing. It is recommended to use a guest operating system, such as Kali Linux, to carry out packet sniffing. For packet sniffing, a person must be familiar not only with using terminals and sniffer tools such as Wireshark, Ettercap, Driftnet, etc. but also with network layer protocols.