In a Nutshell:
Nizam al-Islam presents Islam as a way of life, a discursive tradition, as a civilisation in contrast to the colonially manufactured apolitical and secular religion Islam has been reduced to. It summarises the main breakpoints in Islamic history that distorted its thought, from historic debates of predestination through to contemporary ideologies, and reimagines it in the contemporary age.
Here are some of my thoughts on the book Nizam al-Islam by the Palestinian jurist and activist, Taqi al-Din Nabhani (ra).
The book is presenting Islam emphasising the "socially collective" system of life, that is missing from our societies. Hence the term "nizam" as opposed to din, millet, mabda' etc, the focus being on an organic system that is designed for human societies and its institutional elements that have been removed by foreign powers.
A system of life has a number of important characterising dimensions which the book aims to elaborate - each of which can be compared and contrasted to other systems of life to show their elegance, practicality and comprehensiveness...
The most profound and important aspect has to be the epistemological worldview (ch 1). It provides a meaning for social and personal life, generating a trajectory and aim to allow for a meaningful and fulfilling life (both social and personal), that comprises full obedience with submission to Allah. The worldview also provides the metaphysical explanations of what is "beyond" the continuous flow of sense perceptions we experience - something explored in all civilisations from the ancient Greeks to the contemporary post-modern thinkers, without any successful outcomes.
Then follows an explanation of the "connection" / "nature of interaction" of the metaphysical divine and our material world (ch 2), through a discussion of fate (qada') and universal order (qadar), clarifying some historical accretions.
The ideational nature of the Islamic system that encourages social bonding based on common concepts as opposed to common instincts and sentiment is then elaborated through contrasts with other ideologies, both intellectual and sentimental (ch 3).
All societies produce collective perspectives, values, norms and other social patterns, broadly termed cultures and these cultures manifest over time to bring about a civilisation - something that characterises that society and its culture through visible and physical manifestations of material progress and achievements in all aspects of life. This distinguishes the characterisation of the Islamic civilisation from other civilisations, both contemporaneous and ancient.
The hukm shari and succeeding sections deal with the fundamental issue that has been unsuccessfully grappled by some of the greatest minds of humanity over millennia (studied as ethics in philosophy) namely, how does one derive a normative (or moral) perspective and its necessary rules and means of adoption. This perspective determines all "shoulds" or "right moral conduct" in life - whether in personal, political, economic or collective life. Compare this with Kantian deontological, Benthamite consequentialist, or Dewey Pragmatist alternatives...
Applying this normative perspective in the social realm, through considering the issues surrounding an articulated construction, Nabhani talks through the acceptability of detailing a normative structure for a state and provides a practical example where the system of Islam is illustrated through a potential constitution that can be implemented.