Physics of the Inner Heliosphere gives for the first time a comprehensive and complete summary of our knowledge of the inner solar system. Using data collected over more than 11 years by the HELIOS twin solar probes, one of the most successful ventures in unmanned space exploration, the authors have compiled 10 extensive reviews of the physical processes of the inner heliosphere and their connections to the solar atmosphere. Researchers and advanced students in space and plasma physics, astronomy, and solar physics will be surprised to see just how closely the heliosphere is tied to the sun and how sensitively it depends on our star. The four chapters of Volume I of the work deal with large-scale phenomena: - observations of the solar corona - the structure of the interplanetary medium - the interplanetary magnetic field - interplanetary dust.