Classification is one of the core functions done in the libraries to provide the users for better acces and retrieval of materials. Important and known as standard Classification systems, developed during last two centuries include Dewey Decimal Classification, Cutter’s Expansive Classification, Brown's Subject Classification, Library of Congress Classification, Universal Decimal Classification, Bliss’ Bibliographic Classification and Ranganathan’s Colon Classification. These systems provided with better solution for organization of materials, but have also some limitations. The libraries with rich collections on Islam are also facing classification problems. This book comprises of precise review of literature relevant to this problem along with the collection and analysis of data from such libraries from all main cities of Pakistan. The data has been collected using the interview technique. Classification problems, suitability or unsuitability of standard systems, indigenous response to these problems, library practices in this regard, level of satisfaction with standard and indigenous systems and potential optimal solution of the problem have been included in this study.