This book has been created for patients who have decided to make education and research an integral part of the treatment process. Although it also gives information useful to doctors, caregivers and other health professionals, it tells patients where and how to look for information covering virtually all topics related to gas, from the essentials to the most advanced areas of research. The title of this book includes the word official. This reflects the fact that the sourcebook draws from public, academic, government, and peer-reviewed research. Selected readings from various agencies are reproduced to give you some of the latest official information available to date on gas. Given patients' increasing sophistication in using the Internet, abundant references to reliable Internet-based resources are provided throughout this sourcebook. Where possible, guidance is provided on how to obtain free-of-charge, primary research results as well as more detailed information via the Internet. E-book and electronic versions of this sourcebook are fully interactive with each of the Internet sites mentioned (clicking on a hyperlink automatically opens your browser to the site indicated). Hard-copy users of this sourcebook can type cited Web addresses directly into their browsers to obtain access to the corresponding sites. In addition to extensive references accessible via the Internet, chapters include glossaries of technical or uncommon terms.