Book excerpt: Designed for quick reference, this volume of the Radiology Companion Series is a portable, practical, thoroughly illustrated guide to performing and interpreting gastrointestinal radiologic studies. It presents over 400 images of all common gastrointestinal diseases and disorders, along with succinct, bulleted "key facts" about imaging techniques, pitfalls, radiologic appearance of the disease, and differential diagnosis. Coverage includes state-of-the-art protocols for all current imaging modalities and guidelines on choosing the best studies to evaluate each disorder.