This course book, Understanding the Essentials of Cybersecurity and various threats is expected to acquaint the understudy with the current situation with our insight into Digital data and individuals' protection. We designed the book after carefully considering various university topics in the curriculum. We assure you that this text book is more relevant to undergraduate and postgraduate degrees. Point-by-point conversations about inquiries of minor significance have been kept away from, as these would just blemish the clarity of the blueprint in the plan; basic comments have been presented sometimes where they appeared to be vital, to decide realities, or to legitimize the perspectives taken on issues of crucial significance. Currently, cyber security is an unavoidable aspect of today's digital world. This book examines security attacks, cryptography? symmetric key and asymmetric key cryptography, and its types. There will be a discussion of cybercrimes and their classification, cyberattacks, and types of attacks in Unit 2. Identifying vulnerabilities and exploits in Unit 3, Information Security, Data and Network Security. As part of Unit 4, we have discussed cloud security, its challenges, and mitigation. Intrusion detection and prevention, types of intrusion detection systems, and tools and techniques for studying Internet attacks, network-based attacks, and host-based attacks are discussed in Unit 5. We have briefly elaborated on Ethical Hacking, Foot printing and Reconnaissance, Malware Threats, and Email Tracking in Unit 6. In Unit 7, describe digital forensics, data privacy, and attacks, as well as privacy in different domains, including medical, financial, and others.