Writing a thesis, dissertation or even a doctoral dissertation often poses serious problems for students and researchers at different levels and in different fields. For any student, preparing a dissertation (or a final paper, or a DEA dissertation or a thesis) is the beginning of a major effort. It's like entering a new world, a new environment that requires adaptation. Because doing research means trying to understand your new environment by deploying certain methods.The finalist student is expected to produce "valid knowledge", and he or she must constantly be able to explain how it was produced. They must be able to defend their ideas. Hence he must gradually adopt a certain attitude towards what he has to put forward and the means he has used to achieve it.