This paper provides a comprehensive review of the evolving paradigms of the cloud, fog, edge, and the mobile cloud computing, analyzing their architectures, functional roles, and integration within the contemporary distributed systems. Key advancements in virtualization, security protocols, performance enhancement, and trust frameworks are examined, alongside realworld applications where the mobile, edge, and the 5G-enabled infrastructures address challenges such that latency reduction, scalability, and energy efficiency. The study also explores emerging trends, including AI-assisted orchestration, eco-friendly computing approaches, and hybrid multi-layer architectures, highlighting their role in fostering intelligent and sustainable computing ecosystems. Practical case studies, such as Smart Edge healthcare systems, that illustrate how distributed paradigms enable precise and real-time decision-making. Finally, the paper synthesizes current research and technological insights and outlines potential directions for the development of next-generation distributed computing architectures and frameworks.