This monograph gives an overview about traditional ways of how to examin companies during a due diligence process and will reveal weak spots of not including qualitative aspects including human resource activities and cultural aspects. The author describes how to include these factors during the due diligence process and gives the reader an understanding of why it has such an impact to decide about future success or failure of M&As. Finally, the author describes the possible due diligence process starting with the examination of the own company to the post merger integration phase.