Radiological protection philosophy, regulation and application have evolved significantly over the last 30 years, adapting to the ever-changing landscapes of scientific understanding and societal values. This report provides a methodical assessment of these changes. Starting with radiological protection in the 1970s, it describes the philosophical differences between International Commission on Radiological Protection (ICRP) Publication 26, issued in 1977, and ICRP Publication 60, issued in 1990, as well as the regulatory evolution that was necessary to effectively implement the changes. It then examines the philosophical and regulatory changes between ICRP Publication 60 and ICRP Publication 103 of 2007. Although the regulatory changes needed to implement Publication 103 are, in practice, yet to come, the report provides a seasoned view of what these changes will most likely be, and what efforts will be necessary to successfully implement them.