Additional discussion highlights the current challenges of pain research, covering a range of topics from difficulties in identifying new targets from pre-clinical models to the current regulatory and commercial challenges. This background sets the scene for recent scientific changes in pain research, such as the drive for genetic validation of targets and the derivation of human cell platforms from stem cells. Finally the book covers the discovery and development stories for two pain products approved in the last decade. These case studies for Lyrica and the Butrans patch, give insight into the discovery and development challenges and successes for both an oral and non-oral product.