Synthesizing research on metacognition and intersecting it with studies on second and foreign language writing, Sin Wang Chong puts forward a conceptual framework of metacognition and metacognitive knowledge that is employed as an analytical lens to examine junior secondary EFL students' writing proficiencies. The exploration takes into account three facets of metacognitive knowledge, namely person knowledge, task knowledge, and strategic knowledge. Based on data garnered from interviews, open-ended questionnaires, and think-aloud sessions with students, the book analyzes the three types of metacognitive knowledge - theorized as a system - of junior secondary students with high, average, and low writing proficiencies. Discussion of the findings offers an expanded understanding of the factors that potentially affect students' writing proficiencies, which will inform the teaching of primary and secondary EFL writing teachers to be more learner-centered. The book will appeal to researchers and teachers interested in metacognition and metacognitive knowledge.