Research organizations eagerly acquired these early instruments to explore the capabilities of this new technique. In all, about 200 instruments were in use worldwide by 1975. A number of daunting technical and marketing problems confronted these early entries: non-repeatable results, difficulties analyzing insulators, a lack of familiarity with the technique, and, for the manufacturers, difficulty in identifying applications that could generate a significant instrument market. As a result, most of the original manufacturers had discontinued production by the late 1970s.

Companies who persevered or entered the field later benefited from the earlier pioneering work, producing instruments with new capabilities for a growing number of users. Most developed multi-technique instruments: incorporating complementary capabilities (AES, LEED, SIMS, etc.) to appeal to a larger market. Over time, a broad range of academic and industrial characterization problems emerged for which ESCA was the method of choice.

Looking back over thirty years' experience with ESCA, it is apparent that major advances in understanding, analytical procedures, and instrument design have resolved most of its early shortcomings. Today ESCA is a powerful surface characterization tool widely used in diverse fields from medicine and manufacturing to quantum physics.

This article is a personal account of one person involved in ESCA development over these three decades at Hewlett-Packard, later at Surface Science Instruments, and finally as a research worker using ESCA at Stanford University. I discuss some of my experiences designing and marketing instruments in this emerging field, my thoughts about the key innovations responsible for the success ESCA has enjoyed, and some thoughts about its future development.