This study aims to categorize the existing research related to Japanese extensive reading, and to compile an annotated bibliography of extensive reading in second language learning. First, this paper will review the differences between extensive and intensive reading, and the definition of extensive reading in the second language. Then, based on the existing research, this paper organizes extensive reading activities into three categories based on the environment in which the reading is done and the level of autonomy; these three categories are as follows: 1) extensive reading during class, 2) extensive reading outside the classroom, and 3) autonomous extensive reading. Then, the paper attempts to understand the types of extensive readings activities in terms of their rules and characteristics by categorizing them into four types: 1) novel, shinsho type; 2) NPO type, 3) modified NPO type, and 4) free reading type. Finally, this paper offers an overview of important and current research regarding extensive reading in Japanese, whilst also providing a list of existing research on extensive reading in the second language.