In the case of historical reviews our job is to describe what happened in the past so that we can understand the present or plan for the future. Here we go through existing records and reports and talk to different people to get as true a picture as possible. The archives are reviewed with a rather interrogative manner and with a particular research question / problem in mind. The main problem with using such a method is that we have to rust human memory. Which records selective parts of our reality . it is quite possible that two different people while going through a certain situation or experience, will record or remember different things sometimes they make mistakes or misunderstand. It is therefore important that while using such a method we should cross check on written source with another or a written source with an interview or two interviews with each other. In other words we have to be critical and compare different explanations for the situation or event.