This report is intended to review the field of Resistance Seam Welding (RSEW) and to discuss recent trends in the design and use of the equipment. Since this is an interpretive report@ the presentation is concise and references are available for those who wish to delve deeper into the background upon which the conclusions are drawn. The discussion engendered by this report should point out those areas where additional scientific investigation is required. Some of the claims for recent developments are presented@ based upon information obtained in discussions with users and builders of seam welding equipment. Specific examples are presented and apply to individual applications only