@mukiex
Seriously speaking, this is one the best books to use to start learning the language. After going through many learning resources (Genki, Minna no Nihongo, Marugoto, blahblah), I still believe it's better than these "formal" grammar books out there. At least, you will be more or less capable of reading manga (but with difficulties) after you finish around half of it.
Good luck and happy learnin'!