This is a picture book series for learning hiragana, katakana, alphabets, and numbers. - Title: A, I, U, E, O Train Dictionary - Title: Katakana World Train Dictionary - Title: Numbers and Figures Train Dictionary - Title: Working Cars Train Dictionary - Title: ABC Train Dictionary Thank you for looking. These are picture books that my son loved and read a lot. He read them enthusiastically when he was 2-3 years old and quickly learned hiragana and numbers. There are some bent corners and signs of use. Also, there are marks from a marker on the closed part of the katakana book (see photo 5). There are no writings or tears inside the pages. If you have any questions, please feel free to comment. Thank you.