Question: Please inform me of any book on the importance and the role of ombudsman in Islam and also let me know about some sites.
    Answer: Man has been bestowed with a reasoning faculty which distinguishes him form other creatures. He has not been sent in this world totally blind, rather innate guidance has already been fed into him. This is the very reason that Islam does not go into technicalities and explain details of each and every system. On the contrary, it delineates some principles which must be adhered to in all circumstances. 
    Similar is the case of ombudsman. Providing justice at each and every level is a basic requirement of Islam and for this purpose, it does not give a particular system. Each and every system capable of providing justice in its real sense would be Islamic and it makes no difference that whatever its name is. It may be a judge, a court, a panel of judges, or an ombudsman. The term ‘ombudsman’ is a modern one imported from Scandinavian countries. However, it does not mean that Islamic history is silent in this regard. Throughout various ages of Islamic history, the concept of justice and that of Muhtasib (ombudsman) have remained alive and effective. However, socio-geographical and cultural changes have led to some diversity which is but natural. So if they fall within the purview of principles provided by Islam, they but would be Islamic. 
    It is difficult to pinpoint the name of a book or some site. However, history would provide you with sufficient proof in favour of this institution, right from the Rightly Guided Caliphate to that of modern era. The problem is not the presence of this institution or that of nomenclature but its implementation according to the Islamic principles, which is still awaited as was in the past.