The book "Internet of Things (IoT): Architecture, Protocols, and Applications" explores the transformative world of the Internet of Things (IoT). From its origins as simple sensor networks to a complex ecosystem integrated with AI and machine learning, this book delves into the foundational concepts of IoT, its layered architecture, and the critical role of communication protocols. While IoT promises immense potential, it also faces significant challenges-security vulnerabilities, data privacy concerns, and the need for interoperability. This text addresses these issues while highlighting the opportunities for innovation that arise alongside them. Discover the diverse applications of IoT across smart cities, healthcare, agriculture, and industry, and understand the importance of standards and governance in fostering a secure and collaborative IoT landscape. As we look to the future, explore the exciting convergence of IoT with 5G, AI, and sustainable practices. This comprehensive guide equips readers with the knowledge to navigate the evolving world of IoT, emphasizing the balance between technological advancement and ethical responsibility.