Introduction to the Special Fiftieth Anniversary Issue

As the Ultrasonics, Ferroelectrics, and Frequency Control (UFFC) Society of the IEEE approached its 50th anniversary as a defined society of the IEEE, the Administrative Committee asked that we consider soliciting a set of technical papers that would offer a comprehensive review of the history of the key technical developments in fields of interest to the UFFC Society. The papers received covered technical progress starting with the earliest work developing quartz crystal oscillators needed in World War II. Most of the papers addressed historical development and the state-of-the-art of various forms of acoustic fields and waves currently in use in a wide variety of devices. Other papers review material and device development. While the articles address varied applications and aspects of interest to the three member groups of the UFFC, the breadth of the articles demonstrates the universality of interest in the articles across the Society membership. We would like to thank all of the authors that contributed to this Special Issue, to the many reviewers of the papers for this issue, and for their critical assessment of the quality of the papers.