In an era characterized by unprecedented digital connectivity, protecting sensitive information has become increasingly critical. As communication technologies evolve, so too do the risks of unauthorized access. End-to-End Encryption (E2EE) has emerged as a fundamental component of secure communication, preserving data confidentiality by ensuring that information remains encrypted between sender and recipient exclusively. This chapter presents a multidisciplinary examination of E2EE, synthesizing insights from technical developments, practical implementations, and cross-domain challenges. We examine core encryption technologies—including AES, RSA, and Diffie-Hellman Key Exchange—while analyzing their deployment in platforms such as WhatsApp and their function in safeguarding contemporary communication. Our analysis extends beyond technical considerations to address socio-ethical dimensions, including interface design flaws and the vulnerability of opportunistic E2EE systems to active attacks. We identify notable research gaps, particularly in automated authentication procedures and security for audio channels. The complexities of real-world E2EE implementation necessitate interdisciplinary collaboration. We argue that advancement requires coordinated efforts across computer science, legal studies, social sciences, and design to develop frameworks that balance security requirements, privacy, usability, lawful access, and public trust. This review proposes strategic directions for enhancing E2EE methodologies to address evolving demands of secure communication, emphasizing adaptive solutions that anticipate threats while maintaining robust protection.