One thing I would like to add that the purpose of creating a duplicate service book is that if the Original is lost or damaged due to some reason, the duplicate one may be used henceforth and it will be treated as Original. If it is faced that the number of Service book is not sufficient to prepare a duplicate one, photocopy (attested preferably) of the pages containing entries may be given to the employee concerned, until new lot of Service book are procured, so that in case of any indecent of loss or damage, a new service book can be prepared easily on the basis of the photocopies. This is not the approved process though.