Challenged by increasing competition and globalization, third party logistics service providers (3PLs) can become more successful by focusing on customer loyalty. Within long-term customer relationships, 3PLs can offer more advanced logistics services, mitigate the risk of substitution, realize higher profit margins, and avoid new customer acquisition costs. In order to effectively manage customer loyalty, 3PLs need to be aware of the factors that influence loyalty. In addition, they have to understand the effects of different relationship conditions and cultural background on loyalty formation. These issues are addressed in the present book. First, a model of customer loyalty and its determinants is developed, which is then validated using empirical data from nearly 800 logistics managers in Germany and the USA. Effects of different relational factors on the customer loyalty model are identified and cultural differences between Germany and the USA are revealed.