This revised textbook summarizes the latest research into geochemical processes in marine sediments. It provides a complete representation of the subject and includes the most recent findings following the considerable research into the subject carried out since 1980. A new chapter describes properties, occurrence and formation of gas hydrates in marine sediments. The topics covered include the examination of sedimentological and physical properties of the sedimentary solid phase. The textbook ends with a chapter on model conceptions and computer models to quantify processes of early diagenesis. The book will benefit students and scientists at universities and marine research institutes.