Kanji knowledge alone isn't enough; you also need to know roughly 1,500 vocabulary words to pass the full N4 exam.
To pass the N4, you need to know approximately 250 to 300 kanji in total. This includes the ~100 kanji from N5 plus about 170 new characters specific to the N4 level.
The book is typically divided into sections that help you transition from N5 basics to more complex N4 structures: