The Sea Floor deals with the most important results achieved in Marine Geology over the last three decades. Relevant geophysical, geochemical, sedimentological and paleontological methods are shortly described. They should allow the reader to comment on new results about plate tectonics, marine sedimentation from the coasts to the deep sea, climatological aspects, paleoceanology and the use of the sea floor. The text tries to transmit to the reader the excitement of marine geological research both aboard and in modern laboratories. Basic mineralogical, geochemical, biological and other relevant data and a detailed list of books and symposia are given in an Appendix. The second edition of the Sea Floor is an updated version with many new aspects and illustrations and contains detailed lists of relevant books.