Hydrogen plays a key role in materials, beneficial in some cases, problematic in others. A detailed understanding of hydrogen-based interactions is vital to improvements and possible new applications. This book presents the proceedings of the International Symposium on Hydrogen in Matter (ISOHIM) incorporating contributions focused on semiconductors, normal metal conductors, superconductors, and vacuum systems that deal with hydrogen-matter issues. Broad discussion includes liquid hydrogen storage containers for hydrogen powered vehicles.