This book appears at a time when many other books and ideas are being propogated to justify the status quo of the ummah, and the position of those who are not ruling by what Allah has revealed and to detract from the seriousness of the situation.
This book is a detailed discussion of the extreme views of both the Murji'ah and Khawaarij, which are clouding the ummah's vision as they have done for far too long.
The view of the Murji'ah states that faith is simply the matter of belief in the heart, which no link to action, whilst the view of the Khawaarij is that any sin equals a mjor kuft act which puts a person beyond the pale of Islam.
The author highlights these distorted views, then explains the middle way of Ahl as-Sunnah wa'l-Jamaa'ah, based on the Qur'an and Sunnah, where faith is composed of both belief and action, and it may increase and decrease; while sin does not necessarily equal a major kuft act, but there are some major sins which do consitute major kufr acts and put a person beyond the pale of Islam, such as ruling by something other than what Allah has revealed.
Once this idea is clear in the minds of ordinary Muslims, the Muslim ummah will not accept anything from their governments and rulers except shari'ah, to rule their lives, and they will realize that any other system or law is nothing more or less than kufr in disbelief and a deviation from Islam.