Here’s some recommended books (with affiliate links to Amazon):

 小学自由自在 –

The best way to learn a language is to use native materials like books, textbooks, language settings on devices, music, radio, news, webpages, TV, movies, etc.

This book has been a lot of fun! There are many layers to the amount of information presented in the textbook, but it is organized and presented beautifully!

 
Jazz Up Your Japanese with Onomatopoeia –

One of the best parts of the Japanese language is its ability to capture and express the sounds of the world we live in. Endlessly fascinating, this book makes a great addition to anyone interested in learning Japanese.

 

Kanji de Manga Special Edition: Yojijukugo –

A very cool book with yojijukugo or four character expressions (kind of like English idioms i.e. “what goes around comes around). Each phrase is broken down to explain each individual kanji and finally the phrase is used in a sentence. A manga picture is featured on each page.

 

Japanese Sentence Patterns for Effective Communication –

This is a great reference and lesson aid for Japanese Language learners of any level. Use this for review, or to get you up to speed quickly.

 

学校の怪談　－　School Ghost Story–

Here’s a nice little (intermediate, with furigana) manga about a haunted school with some surprising guest characters.

 
 

Japanese Grammar in Use　–

This is a very practical book. The fact that it is bilingual is a plus. It comes with tons of examples and a CD!

 

ともだちパズル　–

This is a great little manga about a girl and her adventures with her various friends. A nice read and entertaining.

 

おおかみこども雨と雪　－　おおかみこどもあめとゆき　–

This is a perfect book for intermediate readers. This version has furigana so the kanji are manageable. If you want you can watch the movie first, then read the book.
 

Read Real Japanese–

This is a great book for intermediate and above level readers. ALSO, the book comes with a CD of the stories read by a native speaker. This is a great way to practice reading and listening. The stories and the translation are fantastic.

 

Keys to the Japanese Heart and Soul–

This book is by far the best book on the language and culture of Japan I’ve read yet. Gain perspective and lean a ton from this great book.