Several Race to the Top grantees are considering the development of video libraries as one element of their larger teacher and leader effectiveness reforms. Video libraries promise to offer "real world" examples of teaching practice that can be used for a wide range of purposes: providing teachers with concrete evidence of excellent practice aligned with college and career ready standards, serving as examples in interrater reliability training for observers of teaching practice, and so forth. This publication summarizes research about the specifications for video libraries in the Requests for Proposals (RFPs) developed by four States: Delaware, Illinois, New York and Rhode Island. This publication may be particularly useful for policymakers and administrators in State and local educational agencies that may be considering the development of a video library as a strategy for improving teacher and student performance. Below, the publication analyzes the contents and specifications of the RFPs that each State developed for video libraries. The differences between them offer insights into the different use cases for video libraries, as well as the ways States describe them. We ask the reader to keep in mind that this publication documents an emerging practice. It captures a moment in time in the design and procurement of video libraries by Race to the Top grantees, not necessarily best practice.