Fundamentals of Cloud Security offers a structured, framework-based approach to understanding, implementing, and securing cloud environments. Built around the NIST Cybersecurity Framework, it connects identification, protection, detection, response, and recovery to practical applications across AWS, Azure, and Google Cloud. This First Edition text guides readers through readiness assessments, shared responsibility, governance, compliance, and architectural considerations that shape secure, scalable cloud systems. Content explores the cloud threat ecosystem, principles of security and trust, and the strategies, tools, and controls that drive resilient operations. Case studies and real-world examples illustrate how to bridge theory and practice, while coverage of emerging security roles, automated tools, and AI-driven techniques highlights the evolution of cloud protection. Designed to align with cybersecurity and cloud computing programs, it supports modern learning outcomes and prepares learners to address current and future challenges in the field.