This book presents the power links concepts and its relation to information retrieval. power links is a quantitative tool to determine the co-citation relation between tow terms depending on the co-frequency and the distances between instances of the terms. The book concentrate on the concept of field association terms, co-word analysis. This book use the power link as a tool to improve the ranking results of search engines. Also it goes deeper to apply the power link in context spelling checking and text extraction and summarization