This book focuses on early diagnosis of the morphological changes in gastric mucosa, which are believed to be precursors for gastric cancer development. The use of modern imaging techniques in order to reveal and treat early cases of gastric cancer is also discussed. In addition, this book reviews modern data on gastric cancer prevention by means of screening gastric precancerous conditions and changes, as well as estimating the risk of gastric cancer development in individual patients with subsequent proper management for reducing the possibility of neoplastic progression.