To a large extent, American leadership in science has been based on the wide-spread availability of excellent instrumentation: In an earlier era, scientists could make fundamental discoveries with the equivalent of sealing wax and string. Today an occasional worthwhile observation is made with simple tools, but most significant advances depend on the application of complex instrumentation. In many instances appropriate devices make possible a tenfold or greater speed in data collection. In other instances sophisticated equipment permits measurements and experiments heretofore inaccessible. Current trends indicate that, in the future, leadership in science will be even more contingent on pioneering the use of new and increasingly powerful equipment. American scientists are fortunate in having the support of an innovative instrumentation industry that has been a byproduct of federal support of research.