The 21 st century was marked by an "internal audit explosion" in all sectors of the global economy, including government. However, very little is known about its origins, characteristics, scale and impact on public sectors. This thesis advances the emerging and poorly understood field of public-sector internal auditing (IA) by providing the first comprehensive examination of the public-sector reforms that led to and resulted from this IA explosion, covering global, world regions, and country levels of analysis, in dynamic and comparative analytical perspectives.The major implication is that VAMP-inspired public-sector IA reforms are still work-inprogress and their outcomes are difficult to assess, meaning that a significant long-term public-sector adaptation and modification is required in order to achieve desirable outcomes for the IA reforms under the VAMP paradigm. Key issues for future research point to the need to develop better IA data and a theory for public-sector IA.