A Beginner's Guide to Internet of Things Security focuses on security issues and developments in the Internet of Things (IoT) environment. The wide-ranging applications of IoT, including home appliances, transportation, logistics, healthcare, and smart cities, necessitate security applications that can be applied to every domain with minimal cost. IoT contains three layers: application layer, middleware layer, and perception layer. The security problems of each layer are analyzed separately to identify solutions, along with the integration and scalability issues with the cross-layer architecture of IoT. The book discusses the state-of-the-art authentication-based security schemes, which can secure radio frequency identification (RFID) tags, along with some security models that are used to verify whether an authentication scheme is secure against any potential security risks. It also looks at existing authentication schemes and security models with their strengths and weaknesses. The book uses statistical and analytical data and explains its impact on the IoT field, as well as an extensive literature survey focusing on trust and privacy problems. The open challenges and future research direction discussed in this book will help to further academic researchers and industry professionals in the domain of security. Dr. Brij B. Gupta is an assistant professor in the Department of Computer Engineering, National Institute of Technology, Kurukshetra, India. Ms. Aakanksha Tewari is a PhD Scholar in the Department of Computer Engineering, National Institute of Technology, Kurukshetra, India.