いいずなラボ　参考書問題集版 is an app that allows users to study along with the reference books and practice question sets published by Iizuna Shoten Co.LTD. This educational app provides learning materials from a total of 16 books, including 11 English textbooks and 5 Japanese language textbooks.

The English learning materials include "Comprehensive English Evergreen," "Comprehensive English be 3rd Edition," "English Grammar and Usage Vintage New Edition," "English Grammar and Usage Engage," "MEW Core 500," "MEW Days1200," "MEW Expansion 1400," "MEW Frontier 1600," "EG3000," "EG4500," and "Cheer3000."

The Japanese language learning materials consist of "Classical Japanese Vocabulary 330 Revised Edition," "Classical Japanese Vocabulary 300 + Honorifics 30 Revised Edition," "TOP2000 Revised Edition," "TOP2500 Revised Edition," and "Frequently Used Japanese Language Questions 1200."

The app offers six different learning methods, including listening practice, flashcards, exercises, rearranging questions, multiple-choice questions, and video lectures (note: not all learning methods are available for every book).