The document discusses third-party tools that provide alternative interfaces for searching PubMed. It begins with a brief history of access to MEDLINE and the development of PubMed and its APIs. The bulk of the document describes several case studies of third-party tools, grouping them according to themes like semantic searching, visualization, mobile access, and simplification. It concludes with exercises for groups to explore different tools in more depth and discussion questions about adopting ideas from third parties or circumstances for using various tools.