This paper investigates similarities and differences found in all 6 different Middle School English textbook series which are in use in japan. The investigation was conducted in terms of the following three criteria: (1) type of exercises; (2) presentation of word lists; and (3) word selection. The findings of the present study are to serve as a guide for the teacher in grasping those differences so that the teacher using one particular series will know what other areas should be empahsized in class. In addition, some suggestions to the textbook writer were given based upon recent research on language acquisition. The implications of the findings are discussed.