Unicom publishes The Preparatory Course for the JLPT and each book focuses on a specific section of the test. Each book provides an in-depth look at that section of the test. This is especially helpful if you know your weaknesses and want to drill, drill, drill them away.
This book focuses on the upper beginner level N4 Reading section of the test. If you are weak on reading comprehension or sentence structure, this book is for you.