The intent of this book is to help business practitioners and students expand their knowledge of how waiting line analysis can be used to address situations beyond the simple examples they were presented in basic operations courses. Throughout the book, practical examples are given and worked out to aid in understanding the material presented. The first chapters begin with a review of those simple examples and the terminology used for waiting line processes. Following chapters cover more complex concepts related to multiple server situations, less common arrival and service distributions, limited population applications commonly used for maintenance activities, cost trade-offs between adding service capacity versus process improvements, and manufacturing applications.