Context-aware ranking is an important task with many applications. the item recommendation systems (products, movies, ...) and search engine for web pages should be ranked. A simple example for context is the user for system recommendations and requests for search engines. In this book, a general method for ranking and context-aware applications is presented. The second major part of this book is to apply this general theory to the three scenarios of the items, tags and sequential set of recommendations. This book generalizes and builds on work that has received `WWW 2010 Best Paper Award ', the` WSDM 2010 Best Student Paper Award' and `ECML / PKDD Discovery Challenge Award 2009 Best '.