Abstract Even the best and fullest knowledge of the topography, sediment cover, and rock outcrops on the ocean floor (as also on land) leaves many questions about the underlying structure and stratigraphy unanswered. Direct sampling at considerable depth below the bottom can be accomplished only by drilling. Pioneering use of drill holes in the ocean floor resulted from the need to know the composition of the bottom for foundation design in the shallow water of seaports. Similarly, the drilling of oil wells proceeded gradually from land to shallow water to depths now in excess of 300 m. The first well-known offshore drilling for general scientific information was that of the British Royal Society at Funafuti Atoll in 1898 (Halligan, 1904), where a rotary drill operated from the bow of an anchored sailing ship and sampled to a maximum depth of 45 m below the lagoon floor at 30 m. Deep-sea drilling began in earnest with the experimental Mohole project, during which a hole reached a depth of 182 m below the bottom at 3,566 m off western Mexico in April 1961 (Riedel et al. , 1961). In preparation for a larger drilling program, the Joint Oceanographic Institutions’ Deep Earth Sampling program (JOIDES) drilled six holes off eastern Florida during April and May 1965 with bottom penetrations to 320 m in water depths as great as 1,032 m (Bunce et al., 1965). The main program, termed the “Deep Sea Drilling Project,” began in July 1968; the program is funded through 1972.