Are you tired of not understanding this most essential part of the Japanese language than never seems to be the focus of any language learning books or classes? This is a good start. There are a lot of onomatopoeia in Japanese, and it can be overwhelming to try to learn them, but the way this book teaches some of them in short snippets through simple little comics makes it easy. Instead of treating this like a textbook by taking notes, making flashcards, and trying to absorb everything, I took more relaxed approach and casually read a few pages while eating breakfast every morning. I think this is a decent way to study onomatopoeia because there are so many of them.
The dialogue in the comics shows you how onomatopoeia are used in spoken sentences, and there are also sound effects outside of the dialogue like you see in other comics. It's nice that there are explanations in both Japanese and English of what the onomatopoeia means, and English translations of the dialogue. However, if you are looking for a direct translation for the sound effects in the comics, there aren't any-just explanations to help you understand what it's referring to.