This book will be useful for researchers and Professionals that work with UML use cases. Here they will find a survey that was made toward finding better ways to measure and improve the quality of use cases. A short summary of the contents of this book is as follows. Requirements documents tend to be swamped by requirements that are no longer meaningful, descriptions that are unnecessarily long and convoluted, duplication of information, among others. These syntactical problems hinder the overall understandability of requirements documents throughout the whole development process. AIRDoc is a step forward to fill this gap proposing a process that supports the evaluation and improvement of requirements documents specified based on use cases. This process is founded on the elaboration of goals and definition of questions that will be answered by Assertions and metrics. The requirements documents quality is improved by the use of refactorings. This book was extracted from the author's doctoral thesis, published in 2009 by the Federal University of Pernambuco, Brazil.