In most engineering fields, the designer would not feel himself competent if the unresolved uncertainties were as great as those that he has to accept in seismic design problems. Confidence has been somewhat shaken by the record of damage and catastrophe of the last
ten years, especially by the uncomfortable fact that the mechanisms of movement which have 
caused the damage have varied so greatly; there is no sign that nature has exhausted her repertoire. It is not surprising that studies published in recent years contain a high proportion whose findings reflect the thought "things are worse than we thought". Some examples of such studies are referred to, and ideas expressed as to our future needs.