The area off the coasts of Louisiana and Texas out to the edge of the Continental Shelf (water depth 600 feet) is a little larger than the onshore Gulf Coast producing province. Together the onshore and offshore constitute one geologic entity. It is not surprising that exploration of the offshore, using 50-odd years of onshore experience, has resulted in an outstanding discovery record. This record does not suggest that the offshore will eventually produce more hydrocarbons than the onshore. Neither does it suggest that explorationists can relax and assume that they have fewer problems than usual. On the contrary, no group of explorationists ever needed sharper tools and sharper wits if they are to contribute satisfactorily to the problem of making the offshore an economi venture for a large number of operators. Thus the offshore is a challenge to explorationists to improve materially their tools and their thinking at the earliest possible date.