This book presents the state of the art, principles and ideas of Electrophotonic analysis based on Gas Discharge Visualization (GDV) technique, known as well as Electrophotonic Imaging (EPI). This approach, celebrating now 20 years after developing the first GDV instrument, has a strong scientific foundation with thousands of researchers, doctors and practitioners using it in the world. Electrophotonic methods allow to study Energy Fields of humans, water, materials and environment. Conceptual background and practical approaches are presented in this book.The current manual is for those who are actively working with EPI/GDV technology. In recent years, continuing research has accumulated a large volume of experimental data, and doctors have created patient databases with detailed analysis. This data makes it possible to formulate a number of new approaches and ideas. The main purpose of this book is to help experts, doctors, psychologists and researchers to interpret EPI Bioelectrography data. Considering the diverse levels of training and qualifications among our readers, we have tried to present the information simply and directly, and without the use of specialized terms and mathematical expressions wherever possible. For this reason, we only touch briefly on the question of EPI parameters and their use when interpreting data. This book is written in the style of a study aid aimed at learning and consultation rather than for light reading. The material is reviewed with many examples. By reading the book and looking at the images, you will easily assimilate the principle of EPI data analysis.This book summarizes the work of hundreds of people busy with development, research and practical work in EPI Bioelectrography. It is not possible to name all those involved in this work, and it is difficult to single out individual contributions, which is why we would like to thank all those who gave of their energy, knowledge and spirit to create and develop the method of EPI Bioelectrography. Each year the circle of professionals using the EPI method in their work widens, and new research opens undreamt of horizons. We are sure that these are but the first steps in the vast new continent which is opening itself up to us.From 1996 every July in Saint-Petersburg Russia International Scientific Congress "Science, Information and Spirit" hosts hundreds of professionals and interested people from all over the world. Several workshops dedicated to GDV technology are