Kanzen Master

The Kanzen Master Series is maybe the most popular set of textbooks for preparing for the JLPT. They are all well-written and were helpful when I took both the N2 and N1. The Vocabulary books are best used with flashcards.

Whether you get the whole set or individual books, a good way to learn is to use books by different publishers. The JLPT doesn’t use a fixed set of content, so it’s hard to study for. So by triangulating study materials from multiple sources, you should be in a good position to pass.