Over the past few decades, it has become increasingly frequent to come across the co-existence of multiple large-scale assessment surveys within national, subnational, or local settings. Despite the overlapping of tests, time, efforts, and economic resources invested in these “assessment assemblages”, much remains to be learned about their origins, development, tensions, frictions, outcomes, and challenges. Harmony and Cacophony in Large-scale Assessments in Education delves into these issues via a critical lens and offers a case in point against which readers can place their own situations. In other words, it serves as an empirically grounded thinking toolbox to help readers problematize emerging, ongoing, or upcoming challenges related to their large-scale assessment settings.