As part of the corporate responsibility of purchasing, supplier evaluation is one of the most important tasks. In the age of digitalization and global networking, direct contact and personal conversations with suppliers have gained increased importance. This recognized specialist book is considered an essential complement to the standard software programs available on the market. It literally pays off to use the book as a guide through the jungle of diverse conceptual formulations. The book is important for purchasing professionals as well as for young buyers, whether they are working in strategic or operational purchasing. The now available sixth edition has undergone a complete revision, especially in the practical section. Additionally, checklists with review questions for a tiered potential assessment have been included.