International studies, such as the Trends in Mathematics and Science Study, reveal that most teachers rely on textbooks as the basis of their instruction. This is particularly true for new curriculum components. Thus a good alignment between the official curriculums and textbooks is necessary for the classroom implementation of the official curriculums. However, the study of the translation of official curriculums into textbooks is missing in the education literature. The Nature of Science (NOS) content in the Physics curriculums in Mainland China and Hong Kong serves as the context of this exploratory research on official curriculum-textbook translation. In this study, the extent and manner of the translation of the NOS content in the official curriculums into the text book was first investigated through the analysis of the NOS content found in the official Physics curriculums and the Physics text books in Mainland China and Hong Kong respectively. Two sets of textbooks that were widely adopted by schools in each of the two sites were studied against the corresponding Physics curriculum. The findings of the investigation then paved the way for the subsequent identification of the factors that affect the translation of the NOS content in the official curriculums into the textbook content through interviews with the authors, consultants and editors who assisted in determining the content in the textbooks of the two sites. It was found that the major NOS ideas found in the official Physics curriculums at both sites were thoroughly included in the corresponding textbooks, yet the translation of the official curriculums into textbook content was not perfect. In some cases, the textbooks nicely illustrated and elaborated upon the NOS ideas with relevant contexts intended by the official curriculums. In other cases, the alignment was simply are-statement of the curricular specifications onto the textbooks. A number of factors influencing the official curriculum-textbook translation of the NOS content were found in the study. These include authors’ and editors’ belief regarding the benefits brought about by students’ learning of NOS content, students’ background knowledge and reading skills, textbook approval systems and selection practices, teachers’ acceptance towards new NOS content, the absence of NOS-related questions in high-stake examinations and the academic and vocational background of the authors and editors. In addition, the study also revealed other factors that operate differently in the two sites. These include teachers’ criteria of textbook selection, the trial and revision system of textbooks, teachers’ reluctance towards the teaching of new content, and the demand for examination-oriented materials in textbooks. Through synthesizing the factors that influence curriculum implementation found in the literature and the factors that influence the official curriculum-textbook translation as reported by the informants, a model of the factors that affect the translation of official curriculums into textbook content was proposed. The model builds upon and could be analogously compared to the existing model of classroom-level curriculum implementation. Through an enhanced understanding of the official curriculum-textbook translation, the current study provides the missing link in the existing literature on curriculum implementation. / published_or_final_version / Education / Doctoral / Doctor of Philosophy