Principles of Federal Appropriations Law: Third Edition, Volume III (898 pages, PDF): “Our objective in Principles is to present a basic reference work covering those areas of law in which the Comptroller General issues decisions, using text discussion with specific legal authorities to illustrate the principles discussed, their application, and exceptions. As we noted in our first volume, Principles should be used as a general guide and starting point, not as a substitute for original legal research..Publication of this volume completes our process of revising and updating the second edition of the “Red Book” and reissuing it in a 3-volume looseleaf set with cumulative annual updates. This volume and all other updated volumes of Principles, including the annual updates, are available on GAO’s Web site under Key References. The annual updates are only available online.”