This book is designed to help students who already know hiragana and katakana to learn essential Japanese grammar quickly. The explanations are simplified to make self-learning easy.
The book covers the grammar needed to pass the JLPT N5 but combining it with other materials or books will help you feel more comfortable speaking Japanese.
By the end of this book, you should have almost mastered the grammar used in many basic conversations.
The book is divided into short two-page sections, with one page for grammar and another for exercises. If you study a new concept every one or two days you should be able to finish the book in a couple of months.
You can also use the free Japanese learning app 'Coban' for iPhone to supplement your studies.