From the introduction: A deep web book search becomes a challenge as the number of digital libraries increases, and so does the demand of sophisticated users for searching requirements over several digital libraries and search engines before getting to the desired book selections. A scalable, integrated search infrastructure is needed to help users to effectively search structured content information based on identified name entities across heterogeneous digital libraries. IntegraL, an NSF funded project, is a lightweight system that aims to integrate multiple digital libraries, including book search engines, and meta-search engines by using link analysis (Song & Bieber 2008). One of the objectives of IntegraL is to allow users to flexibly enable or disable the use of the subscribed libraries as plugins through a graphical administrative page. In the following we would like to review why an infrastructure is necessary for integrating multiple digital libraries, describe how IntegraL is an innovative way of expanding the use of multiple digital libraries and book search engines at the user’s preference, list benefits of using IntegraL, and conclude our study.