In early 2021-22, the Flexible Phonics reading intervention, a large-scale randomised controlled trial, took place in 118 schools in England and involved nearly 3,000 children. This study aimed to provide valuable insights into the success of largely school-based education trials. The Flexible Phonics trial proved to be not only an important experiment in improving children's literacy, but a case study in which the methodology of single randomised controlled trials in education can be considered. "Reading Randomised Controlled Trials" investigates the complexities of conducting randomised controlled trials in the field of education and how they can be seen as a cultural activity. The book emphasises the human operations, decision-making, and actions that drive such trials, which are often overlooked in published reports. Through the case study of Flexible Phonics, the book highlights the key differences between scaled educational trials and other types of trials, such as pharmaceutical trials. The additional focus on early childhood literacy is of significant educational importance, particularly in the context of UK school partial closures in 2020 and 2021 during the COVID-19 pandemic. "Reading Randomised Controlled Trials" is ultimately a unique resource on the implementation of randomised controlled trials in authentic school contexts and for the sustained improvement of practice in education.