While I can't speak for the N3 vocab book, at least for N2, there is absolutely no English. This book is entirely in Japanese. (The N3 grammar book did contain minimal English, to compare.)
The vocabulary is separated by themed sections (人間、生活、趣味、仕事、matching terms, grammatical/meaning similarities, etc.) and there is an entire index in the back with all the words covered (ordered alphabetically) and their corresponding pages. Do note that there is less furigana in this book compared to the N3 grammar, and the words do not have definitions, so you will need to use a dictionary of some kind to assist you. (Some of the answers in the back to have explanations that cover meaning, but the majority do not.)
At the beginning of each vocab list in the beginning of the book are also prompts for writing exercises or a one question quiz to help reinforce the vocabulary learned on those pages. I definitely recommend giving them a go (and finding a native speaker to correct you if possible), since the topics are pretty common conversations. (Family, work, food, health, etc.) They eventually switch to being just extra quiz questions.
Each section has their own set of test-like questions to review the material. (All answers are included in the back of the book. Most do not offer explanations, heads up.) Then there is a final mock test section that has 40 questions.
While I don't think there's this misconception, just in case, I do want to mention that most of the vocab in this book is not obscure or rare. A lot of these words are insanely common, thus as you get more advanced, and want to both understand and articulate yourself more complexly, these words can be quite useful and important.
I do think this book has a lot of value, and I would've liked to have taken more time with it to really absorb the material. This isn't a fast book to get through. Be prepared to put in some work. If you're studying for the JLPT, I would say this is worth picking up. Especially since my Japanese tutor also highly recommended it.